CA2035962C - Wide area cordless telephone system capable of receiving incoming group address calls - Google Patents
Wide area cordless telephone system capable of receiving incoming group address callsInfo
- Publication number
- CA2035962C CA2035962C CA002035962A CA2035962A CA2035962C CA 2035962 C CA2035962 C CA 2035962C CA 002035962 A CA002035962 A CA 002035962A CA 2035962 A CA2035962 A CA 2035962A CA 2035962 C CA2035962 C CA 2035962C
- Authority
- CA
- Canada
- Prior art keywords
- cordless
- signal
- speech
- group
- channel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/16—WPBX [Wireless Private Branch Exchange]
Abstract
ABSTRACT OF THE DISCLOSURE
In a wide area cordless telephone system, an individual-call signal is generated if an incoming call from the telephone network is an individual call to one of cordless stations of a group and a group-call signal is generated if it is directed to all cordless stations of the group. A
group of access units are associated with the cordless station of each group to establish a control channel and speech channels with the cordless stations. The access units respond to the individual-call signal by transmitting a speech-channel identifier to one of the cordless stations through the control channel and transmitting a ringing signal through a speech channel specified by the speech-channel identifier. In response to the group-call signal, speech-channel identifiers are successively transmitted from the access units to the cordless stations through the control channel and group ringing signals are respectively sent to the cordless stations through speech channels specified by the speech-channel identifiers. In a modified embodiment, the cordless stations receive pairing identifiers each containing a pair of an access unit identifier and a cordless station identifier and transmit a response containing one pairing identifier that specifies the own station. The access units also receive pairing identifiers from the controller for detecting a match with those received from the cordless stations. If a match is detected by each access unit, it is entitled to send a speech-channel identifier to the cordless station which is specified by the matched identifiers.
In a wide area cordless telephone system, an individual-call signal is generated if an incoming call from the telephone network is an individual call to one of cordless stations of a group and a group-call signal is generated if it is directed to all cordless stations of the group. A
group of access units are associated with the cordless station of each group to establish a control channel and speech channels with the cordless stations. The access units respond to the individual-call signal by transmitting a speech-channel identifier to one of the cordless stations through the control channel and transmitting a ringing signal through a speech channel specified by the speech-channel identifier. In response to the group-call signal, speech-channel identifiers are successively transmitted from the access units to the cordless stations through the control channel and group ringing signals are respectively sent to the cordless stations through speech channels specified by the speech-channel identifiers. In a modified embodiment, the cordless stations receive pairing identifiers each containing a pair of an access unit identifier and a cordless station identifier and transmit a response containing one pairing identifier that specifies the own station. The access units also receive pairing identifiers from the controller for detecting a match with those received from the cordless stations. If a match is detected by each access unit, it is entitled to send a speech-channel identifier to the cordless station which is specified by the matched identifiers.
Description
TITLE OF THE INVENTION
2"Wide Area Cordless Telephone System Capable Of 3Receiving Incoming Group Address Calls"
SThe present invention relates generally to cordless telephone 6systems connected to a public or private switched telephone netvvork, 7and more specifically to the reception of incoming calls from the 8telephone network to the wide area co dless telephone system.
9The current wide area cordless telephone system for business 10applications serves divided business areas. It includes a radio contro 11unit connected to a public or private switched telephone ne~Nork and 12access units which are divided into groups corresponding to the 13 business areas. The access units in each area are located at s~rategic 14 points for establishing radio channels with cordless stations located in 15 the same area as the access units. The radio control unit monitors the 16 location of each cordless stations through the access units by storing the 17 locations of the cordiess stations and constantly updating the stored 18 records in order to respond quickly to an originating call to, or an 19 incoming call, from the network.
20 With the current system, cordless stations are uniquely assigne 21 address numbers. All incoming calls from the network are treated as an 22 individual call directed vnly to one of the cordiess stations which is 23 addressed. Therefore, the absence of the addressed user rnay cause a 24 delay in answering the cail, and hence, a neeci arises to allow all 2S incoming calls to be answered by any of the users of each business 2 6 area.
27SUMMARY OF THE iNVENTlON
2 8It iS therefore an object of the present invention to provide a wide .
~, .
, ' area cordless telephone system which enables incoming calls to be 2 answered by any users.
SThe present invention relates generally to cordless telephone 6systems connected to a public or private switched telephone netvvork, 7and more specifically to the reception of incoming calls from the 8telephone network to the wide area co dless telephone system.
9The current wide area cordless telephone system for business 10applications serves divided business areas. It includes a radio contro 11unit connected to a public or private switched telephone ne~Nork and 12access units which are divided into groups corresponding to the 13 business areas. The access units in each area are located at s~rategic 14 points for establishing radio channels with cordless stations located in 15 the same area as the access units. The radio control unit monitors the 16 location of each cordless stations through the access units by storing the 17 locations of the cordiess stations and constantly updating the stored 18 records in order to respond quickly to an originating call to, or an 19 incoming call, from the network.
20 With the current system, cordless stations are uniquely assigne 21 address numbers. All incoming calls from the network are treated as an 22 individual call directed vnly to one of the cordiess stations which is 23 addressed. Therefore, the absence of the addressed user rnay cause a 24 delay in answering the cail, and hence, a neeci arises to allow all 2S incoming calls to be answered by any of the users of each business 2 6 area.
27SUMMARY OF THE iNVENTlON
2 8It iS therefore an object of the present invention to provide a wide .
~, .
, ' area cordless telephone system which enables incoming calls to be 2 answered by any users.
3 Another object of this invention is to provide a wide area cordless 4 telephone system capable of selectively responding to individual calls s and group calls.
6 According to a first aspect of the present invention, there is provided 7 a wide area cordless telephone system which covers a plurality of 8 service areas in each of which a group of cordless stations are located.
9 The system comprises a controller connected to a telephone network 10 for generating a group-call signal when an incoming cail from the 11 telephone network is directed to all cordless stations located in a 12 cornmon service area. A plurality of access units are divided into 13 groups corresponding to the service areas. The access uni~s located in 14 each service area establishes a radio control channel and a plurality of 15 radio speech channels with the cordless stations of the same group as 16 the access units, and are responsive to the group-call signal from the 17 controller for successively transmitting speech-channel identifiers to the 18 cordless stations through the control channel and transrnitting ringing 19 signals respectively to the cordless stations through the speech channels 20 which are specified by the successively transmitted speech-channel 2 1 identifiers.
22 According to a second aspect of the present invention, the 23 controller generates an alert signal containing a plurality of pairing 24 identifiers when receiving an incoming call from the telephone network 25 which is directed to all cordless stations of ~he same group, and 26 successively generates standby signals each containing a different one 27 of the pairing identifiers. A specified one of the access units is 2 ~ responsive to the alert signal from the controller for transmitting a copy ~ ;' ` , -.
, of it to each of the cordless stations through the control channel and 2 causing the cordless stations to successively return respective ones of 3 ~he pairing identifiers through the control channel. The access units are 4 respectively responsive to the standby signals from the controller for s respectively storing a pairing identifier contained in a respective one of 6 the standby signals. Each of the access units is responsive to one of the 7 pairing identifiers from the cordless stations if it matches the stored 8 pairing identifier for transmitting a speech-channel identifier to the 9 cordless station which is specified by the stored pairing identifier through the con~rol channel. A ringing signal is sent to the specified 11 cordless station through a speech channel specified by the transmitted 12 speech-channel identifier.
13 Preferably, the controller further generates an individual-call signal if 14 an incoming call from the network is an individual call directed to one of the cordless stations. The access units are further responsive to the 16 individual-call signal for transmitting a speech-channel identifier to one 17 of the cordless stations through the control channel and transmitting a 18 ringing signal through a specified speech channel.
The present invention will be described in further detail with 21 reference to the accompanying drawings, in which:
22 Fiy. I is a block diagram of a wide area cordless ~elephone system 23 embodying the present invention;
24 Figs. 2A, 2B and 2C are flowcharts illustrating programmed 2s sequences of instructions performed respectively by the radio control 2 6 unit, access unit and cordless station according to a firs~ embodiment of 27 the present invention;
2 8 Fig. 3 is a view illustrating the overall operation of the first N~-31 5 embodiment as well as a second embodiment when an incoming signal 2 from the PBX is an individual call;
3 Fig. 4 is a view illustrating the overall operation of the first 4 embodiment when the incoming signal from the PBX is a group call;
Figs. 5A, 5B and 5C are flowcharts illustrating programmed 6 sequences of instructions performed respectively by the radio control 7 unit, access unit and cordless station according to the second 8 embodiment of the present invention; and g Fig. 6 is a view illustrating the overall operation of the second 10 embodiment when an incoming signal from the PBX is a group call.
12 Referring now to Fig. 1, ~here is shown a wide area cordless 3 telephone system embodying the present invention. The whole area of 4 the system is divided into service areas 6. Only two service areas 61 and 15 62 are shown for purposes of simp!icity. Corresponding to service 16 areas, the whole system is divided into subsystems, each comprising a 7 radio control unit 3, access units 4 and cordless stations 5. In the 18 illustrated embodiment, radio control units 31 and 32 are respectively 19 associated with service areas 61 and 62 and connected to line terminals 20 of a private branch exchange 2 to which ordinary telephones 7 may 21 also be connected. The PBX is in turn connected through exchange 22 lines to the public switched telephone network 1. Calls between stations 23 belonging to different service areas are made via the PBX.
24 Cordless stations 5 are divided into groups corresponding to servke 25 areas 61 and 62. Access units 4 are likewise divided into groups 26 corresponding to service areas 6, the access units of each group being 27 located at strategic poin~s of the own service area. For convenience of 28 system description, each service area has as many cordless stations 51 .
,- ' . . - ~ .
, '~
- 5k as there are access units 41 ~ 4k. Access units 4 are connected to 2 the corresponding radio control unit 3 to establish two-way radio 3 channels to cordless stations 51 through Sk which belong to the same 4 service area. Incoming calls from the PBX are made on a per individuai s (or per station) basis or on a per group (or per area) basis. The term 6 "group" in this specification refers to the cordless stations belonging to 7 each service area. In response to a group-based incoming call (or 8 simply, a group call), ringing signals are transmitted to all cordless 9 stations of each service area to alert the users of the same group.
10 Whereas, in response to an individual call, only one uniquely addressed 11 cordless station is alerted in a manner known in the art.
12 A service console unit 8 is connected to radio control units 3 for 13 setting various systern parameters to configure a wide-area cordless 14 telephone system that is particularly tailored to the needs of the users.
Each subsystem has a fuil-duplex control channel and several full-16 duplex speech channels. The control channel is used for exchanging 17 control signals during call setup periods before connections are 18 established on a speech channel. In a well known manner, each of the 19 access units and cordless stations is provided with a radio transceiver 20 and frequency synthesizers for establishing a connection between them 21 in response to a channel switching signal using a microprocessor-based 22 controller. Similarly, each radio control unit includes a microprocessor-23 based controller for providing overall subsystem control.
24 The signal exchanged between each radio control unit and each 25 access unit and the signal exchanged between each access unit and 26 each cordless station are transrnitted as a 214-bit packet containing a 27 preamble, a frame sync, a group identifier, check bits, a control field 2 8 and a data field. The control field indicates the type of call (individual or .., ~.
group) and a channel identifier. The data field contains a called station 2 address number, a group address number, a channel identifier, and a 3 pairing identifier which will be used in the second embodiment of this 4 invention for pairing an access unit and a cordless during an incoming S group call.
6 In Figs. 2A, 2B and 2C, routines of programmed instructions are 7 iilustrated for processing an incoming individual call and an incoming 8 group cali from the PBX according to a first embodiment of the present g invention, with Figs. 2A, 2B and 2C corresponding to the instructions performed by the microprocessor-based controllers of radio control unit 11 3, access unit 4 and cordless station 5, respectively.
12 In Fig. 2A, the program execution of each radio control unit starts 13 with decision step 21 which determines whether the incoming call is an 14 individual or group call. If decision is made in favor of an individual call, exit is to operations step 22 which directs the sending of a standby 16 signal which is a command signal for tuning a received access unit or 7 cordless station to the control channel. This standby signal is sent to 18 one of the associated access units to cause it to switch to the specified 19 control channel for readying to receive a forthcoming alert signal. Exit 20 then is to decision step 23 which checks to see if an acknowledgment 21 signal is returned from the access unit. If there is none, control repeats 22 step ~2 to retransmi~ the standby signal. If the answer is affirmative in 23 step 23, operations step 24 is executed hy sending an alert signal to that 24 access unit, containing the address, or identifier of the called station. If 2 5 an acknowledgment is received from the access unit (step 25) in 26 response to this alert signal, control moves to step 26 to determine if an 27 "alert response" signal is returned from the access unit, indicating that 28 the alert signal has been relayed through the access unit and received - , .
,'' , by the called station to invoke a series of preliminary actions necessary 2 for it to accept the call. Control then goes to step 27 to check to see if 3 an "end-of-connection" signal is returned from the access unit, indicating 4 that the called station is ready to accept the incoming call. If it is, control S advances to step 28 to send a ringing signal to the access unit to alert 6 the user. If a negative decision is made in each of steps 25, 26 and 27, 7 control returns to step 24 to retransmit the alert signal. When the called 8 station goes off hook, an off-hook signal is transmitted from the called 9 station and relayed by the access unit to the radio control unit. Decision 10 step 29 is provided to check to see if the off-hook signal is received from 11 the access unit. If the answer is affirmative, control moves to the end of 12 the incoming call processing routine and enters a talking routine, not 1 3 shown.
14 If the incoming call is a group call, step 30 is executed by setting a 15 variable i to one. Exit then is to step 31 which directs the sending of a 16 standby signal to access unit 4j to cause it to switch its transceiver to the17 radio control channel of the subsystem in order to make it quickly 18 respond to a signal from the RCU and send a copy of it to cordless 19 stations. If an acknowiedgment signal is returned fro access unit 4j (step 20 32), controi advances to step 33 which directs the sending of an alert 21 signal to access unit 4j, containing the address ~ one of the cordless 22 stations of the called group. I~ an acknowledgment signal is returned 23 from access unit 4j (step 34), control proceeds to step 35 to check to see 24 if an alert response signal is received. This signal corresponds to the 25 alert response of step 26. As will be understood as the description 26 proceeds, the addressed cordless station responds to the aler~ signal 27 and returns an alert response containing in it the address of the own 2 8 station and invokes a series of preliminary actions to receive the call. !f ~, . .
.. . .
~, , the answer is affirmative in step 35, end-of-connection check is made 2 (step 36). If the connection is established, control moves to step 37 to 3 increment variable i by one and proceeds to step 38 to check to see if i 4 = k. If the answer is negative, control returns to step 31 to repeat the s process so that the next cordless station is alerted and a connection is 6 established to it. By repeating ~he process until i = k, all cordless stations 7 of the called group are alerted and connections established.
8 Control now exits the loop and enter3 step 40 to reset variable i to 9 one to initiate a ringing sequence. A ringing signal is sent to access unit 1~ 4j (step 41), and variable i is incremented by one (step 42) and checked 11 against the value k (step 43) to see if there is a match or mismatch 12 therebetNeen. If i is smaller than k, steps 41 and 42 are repeated so that 13 ringing signals are successively sent to access units 41 through 4k and 14 the users of all stations of the called group are alerted in rapid 15 succession. If one of the users answers the group call, an off-hook 16 signal is sent from that user station, containing in it the address of the 17 station, and relayed through the associated access unit and received by 18 the radio control unit (step 44). Exit then is to step 45 which directs the 1 9 sending of ring trip signals to all access units other than the unit from 20 which the off-hook signal has been received.
21 In Fig. 2e, the program execution of each access unit begins with 22 decision step 51 which checks to see if a standby signal is received from 2 3 the associated radio control unit. If it is, control exits to step 52 to tune its 24 transceiver to the control channel and returns an acknowledgrnent signal 2s to the RCU (step 53). Exit then is to step 54 which checks to see if an 26 alert signal is received frorn the RCU. If the answer is affirmative, control27 exits to step 55 to return an acknowledgement signal to the RCU and 28 goes to step 56 to send an alert signal to the associated cordless station.
.
Exit then is to step 57 to check to see if there is an alert response from 2 the cordless station. If there is one, control moves to step 58 to return 3 an alert response to the RCU and sends a speech channel identifier to 4 the cordless station (step ~9). Control proceeds to step 60 to tune to a speech channel specified by the channel identifier, and goes to step 61 6 to determine if there is an end-of switching signal from the cordless 7 station signifying that it has switched to the specified speech channel. If8 the answer is negative, control exits to step 70 to switch the transceiver 9 of the access unit to the control channel, and control returns to step 51.
If the answer is affirmative, control exits to step 62 to check to see if an interference check signal is received from the associated cs rdless station 12 indicating that no interference occurs on the specified speech channel.
13 If the answer is negative, control exits to step 70, and if affirmative, it14 moves to step 63 to return an end-of-connection signal to the RCU
indicating that a call attempt to that cordiess station is successful. On 16 receiving this end-of-connection signal, the radio control unit sends a 17 ringing signal to the access unit wh;ch checks it (step 64) and 1~ regenerates it (step 65) for transmission to the associated cordless 19 station. If an off-hook signal is received from the cordless station (step 66), the access unit returns an off-hook signal to the RCU (step 67). If no 21 off-hook signal is received, control moves to step 68 to check for the 22 presence of a ring trip signal from the RCU. If there is one, a ring trip 23 signal is regenerated by the access uni~ and transmitted to the cordless 24 station (step 69).
In Fig. 2C, the program execution of each cordless station begins 2 6 with decision step 71 which checks to see if there is an alert signal from 27 the associated access unit. If ~here is one, control moves to step 72 to 2 8 return an alert response to the RCU. Exit then is to step 73 to check for the presence of a speeth channel identifier from the access unit. If there 2 is one, control exits to step 74 to tune its transceiver to a speech channel 3 specified by the channel identifier. An end-of-switching signal is sent to 4 the access unit (step 75) and interference is checked (step 76). If no interfering signal is present on the speech channel, the cordless station 6 transmits an interference check signal to the access unit (step 77). If 7 interference exists, control advances to step 84 to switch its transceiver to 8 the control channel and returns to step 71. Following the transmission of 9 the interference check signal, the cordless station waits for the receptionof a ringing signal (step 7~) and activates its ringer (step 7~) in response 11 to it. If the cordless station goes off (step 80), an off-hook signal is sent 1 2 to the access unit (step 81), containing in it the station address. If the 13 ringing signal goes unnoticed by the station, control exits to step 82 to 14 check for the presence of a ring trip signal. If the answer is negative, control returns to step 80, and if the answer is affirmative, control 16 proceeds to step 83 to deactivate the ringer and exits to step 84 to 17 switch the station transceiver to the control channel.
18 The overall operation of the first embodiment of the present 19 invention will be fully understood with reference to Figs. 3 and 4 in which operational sequences for individuai and group calls are 21 respectively illustrated.
Z2 If an incoming call received by a radio control unit from the PBX is 2 3 an individual cali (Fig. 3), a standby signal 200 is transmitted from the 24 RCU to an access unit which returns an acknowledgment signal 201 to 2 5 the RCU. The latter then sends an alert signal 202 to the access unit 2~ which returns an acknowledgment 203 and sends an alert signal 204 to 27 a called sta~ion, containing in it the adclress of the called station. The 28 called station recognizes that an incoming call is forthcoming and , re~urns an alert response 205 to the access unit, containing in it the own 2 address number. The access unit returns an alert signal 207 to the RCU
3 and sends back a speech channei identifier 206 to the called station to 4 cause it to switch to a specified speech channel. When this switching is S complete, the called station sends an end-of-switching signal 208 to the 6 access unit and provides an interference check. If no interference 7 occurs, it sends an interference check signal 209 to the access unit, 8 which responds to it by retuming an end-of-connection signal 210 to the 9 RCU. A ringing signal 211 is then ~ransmitted from the RCU to the 10 access unit which relays it as a signal 212 to the called station.
11 If the incoming call from the PBX is a group call (Fig. 4), a standby 1 2 signal 300 is sent from the RCU to an access unit #1, which returns an 13 acknowledgment signal 301 to it and switches its transceiver to the 14 control channel. The RCU then sends an alert signal 302 to access unit 15 #1, which sends a copy 304 of the alert signal to a cordless station #1.
16 Following the reception of acknowiedgment signal 303, the RCU sends a 17 standby signal to access unit #2, which tunes its transceiver to the 18 control channei and returns an acknowledgment signal 3Q6 to the RCU.
19 On the other hand, cordless station #1 returns an alert response 307 to 20 access unit #1, containing in it the address number of station #1. A copy 21 308 of the alert signal is returned from access unit #1 to the RCU, and a 22 speech channel identifier 309 is sent ~o station #1. S~ation #1 switches its 23 transceiver from the control channel to a speech channel specified by 24 the channel identifier and returns an end-of-switching signal 310 to 2 s access unit #1, followed by an interference check signal 31 1 if no 26 interference is detected on the speech channel. Access unit #l 27 responds to interference check signal 311 by returning an end-of-28 connection signal 312 to the~RCU.
, -:
' The transmission of alert signal 302 marks the beginning of a 2 sequence 1 for the exchanging of signals between access unit #1 and 3 station #1 and the reception of end-of-connection signal 312 marks the 4 end of the sequence 1. Similar events occur during a sequence 2 for the S exchanging of signals between access unit #2 and cordless station #2 6 except for the transmission of a standby signal to another access unit if 7 access unit #2 is the last one. Thus, similar sequences are repeated as 8 many times as there are access units, so that the ringers of all cordless 9 stations of the called group are activated ~o alert all users of the called 1 û group.
11 At the end of sequence 2, a ringing signals 313 and 314 are 12 successively sent from the RCU to access units #1 and #2, respectively, 3 and relayed as copies 315 and 316 of the ringing signals to stations #1 14 and ~2, respectively. If station #1 goes off hook, it sends an off-hook 15 signal 317 to access unit #1 and a copy 318 of this signal is returned 16 from access unit #1 to the RCU. In response to the off-hook signa3 318, 17 the RCU sends a ring trip signal 319 to access unit #2, which relays a 18 copy 320 of the ring trip signal 319 to station #2 to deactivate its ringer.
19 It is seen that such ring trip signals will be sent to other cordless stations if 20 more than two cordless stations are provided.
21 A second embodiment of the present invention is shown in Figs. SA, 22 SBandSC.
2 3 In Fig. 5A, the program execution of each radio control unit starts 24 with decision step 101 which determines whether the incoming call is an individual or group call. If an individual call is received, exit is to 26 operations step 22 of Fig. 2A to perform instructions shown therein in a 27 manner as described above. If a group call is received, control exits to 2 8 step 102 to send a group alert signal to one of the access units. This , .
NE-31 ~
group alert signal contains a plurality of pairing identifiers indicating 2 access units and cordless stations which establish a channel 3 therebetween when responding to an incoming group call. As will be 4 described, the access unit receiving the group alert signal from the RCU
S sends a copy of this signal to all cordless stations of the called group.
6 Exit then is to decision step to check for the presence of an 7 acknowledgment signal from that access unit. If the answer is 8 affirmative, control goes to step 104 to successively send group standby 9 signals to all access units other than one to which the group standby 10 signal has been sent. Each of these group standby signals contains a different pairing identifier. Following a timeout period (step 105) in 12 which the RCU checks for the presence of acknowledgment signals from 13 all the receiving access units, control proceeds to step 106 to check for 14 the presence of an end-of-connection signal from one of the access 1 s units. If there is one, a ringing signai is sent to that access unit (step 107).
16 Control proceeds to step 108 to check to see if the ringing signal is sent 17 to all access units to which the group standby signals have been 18 transmitted. If the answer is negative, control repeats the execution of 19 steps 106 and 107, and if the answer is affirmative, it proceeds to step 1û9 to check for the presence of an off-hook signal. If there is one, 21 control advances to operations step 110 which directs the sending of 22 ring trip signals to the access units other than the one from which the 23 off-hook signal has been received.
24 In Fig. 5B, the program execution of each access unit starts with decision step 111 which determines which signal the access unit has 2 6 received. If the signal is indicative of individual cal, controi moves to step 27 112 to return an acknowledgment signal to the RCU. An aiert signal 2 8 containing a called station address is sent to the stations (step 113). If an - ~-,, - ~
,, ., ~ ,~
: ~ ;
alert response is no~ received within a specified timeout period ~step 2 114), control returns to step 111 to repeat the process.
3 If the signal received from the RCU is a group alert signal, control 4 exits to step 128 to return an acknowledgment signal to the RCU and s moves to step 129 to send a group alert signal containing a different 6 pairing identifier to each cordless station of the called group, and returns 7 tostep111.
8 If the signal received from the RCU is a group standby signal, exit 9 then is to step 130 to return an acknowledgment signal and proceeds to 0 step 131 to store the pairing identifier contained in the received group t 1 standby signal. Exit then is to step 132 to check for the presence of a 12 group alert response signal from a cordless station, containing a pairing 3 identifier. If there is one, exit is to step 133 in which the pairing identifier 14 received from the cordiess station is compared with the pairing identifier received from the RCU to detect a match or mismatch therebetween. If 16 a mismatch is detected, control returns to step 132 to repeat the 1 7 process.
1 8 If the answer is affirmative in step 114 or a makh is detected in step 19 133, exit then is to step 115 to send a speech channel identifier to the access unit that has retumed the individual or group alert signal, 21 followed by step 116 to tune to a speech channel specified by the 22 channel identifier. An alert response signal is then sent to the RCU (step 23 117) and the presence of an end-of-switching signal from the cordless 24 station is checked (step 118). If there is one, control proceeds to step 119 to check for the presence of an interference check signal from the 2 6 station. If there is one, control goes to step 120 to return an end-of-27 connection signal to the RCU. Control then checks for the presence of a 28 ringing signal from the RCU (step 121 ) and moves to step 122 to send a ringing signal to the cordless station. The presence of an off-hook 2 signal frorn the station is then checked (step 123). If the answer is 3 affirrnative, control returns an off-hook signal to the RCU (step 124~, and 4 if negative, control proceeds to step 12~ to check to see if a ring trip 5 signal is received from the RCU. If it is, control proceeds to step 126 to 6 send a ring trip signal to the cordless station, and goes to step 127 to 7 switch the access unit to the control channel. Following the execution of 8 step 127, control returns to step 111. If negative decision is made in 9 each of steps 118, 119 and 121, control exits to step 127, and if negative 10 decision is made in step 125, control returns to step 123.
6 According to a first aspect of the present invention, there is provided 7 a wide area cordless telephone system which covers a plurality of 8 service areas in each of which a group of cordless stations are located.
9 The system comprises a controller connected to a telephone network 10 for generating a group-call signal when an incoming cail from the 11 telephone network is directed to all cordless stations located in a 12 cornmon service area. A plurality of access units are divided into 13 groups corresponding to the service areas. The access uni~s located in 14 each service area establishes a radio control channel and a plurality of 15 radio speech channels with the cordless stations of the same group as 16 the access units, and are responsive to the group-call signal from the 17 controller for successively transmitting speech-channel identifiers to the 18 cordless stations through the control channel and transrnitting ringing 19 signals respectively to the cordless stations through the speech channels 20 which are specified by the successively transmitted speech-channel 2 1 identifiers.
22 According to a second aspect of the present invention, the 23 controller generates an alert signal containing a plurality of pairing 24 identifiers when receiving an incoming call from the telephone network 25 which is directed to all cordless stations of ~he same group, and 26 successively generates standby signals each containing a different one 27 of the pairing identifiers. A specified one of the access units is 2 ~ responsive to the alert signal from the controller for transmitting a copy ~ ;' ` , -.
, of it to each of the cordless stations through the control channel and 2 causing the cordless stations to successively return respective ones of 3 ~he pairing identifiers through the control channel. The access units are 4 respectively responsive to the standby signals from the controller for s respectively storing a pairing identifier contained in a respective one of 6 the standby signals. Each of the access units is responsive to one of the 7 pairing identifiers from the cordless stations if it matches the stored 8 pairing identifier for transmitting a speech-channel identifier to the 9 cordless station which is specified by the stored pairing identifier through the con~rol channel. A ringing signal is sent to the specified 11 cordless station through a speech channel specified by the transmitted 12 speech-channel identifier.
13 Preferably, the controller further generates an individual-call signal if 14 an incoming call from the network is an individual call directed to one of the cordless stations. The access units are further responsive to the 16 individual-call signal for transmitting a speech-channel identifier to one 17 of the cordless stations through the control channel and transmitting a 18 ringing signal through a specified speech channel.
The present invention will be described in further detail with 21 reference to the accompanying drawings, in which:
22 Fiy. I is a block diagram of a wide area cordless ~elephone system 23 embodying the present invention;
24 Figs. 2A, 2B and 2C are flowcharts illustrating programmed 2s sequences of instructions performed respectively by the radio control 2 6 unit, access unit and cordless station according to a firs~ embodiment of 27 the present invention;
2 8 Fig. 3 is a view illustrating the overall operation of the first N~-31 5 embodiment as well as a second embodiment when an incoming signal 2 from the PBX is an individual call;
3 Fig. 4 is a view illustrating the overall operation of the first 4 embodiment when the incoming signal from the PBX is a group call;
Figs. 5A, 5B and 5C are flowcharts illustrating programmed 6 sequences of instructions performed respectively by the radio control 7 unit, access unit and cordless station according to the second 8 embodiment of the present invention; and g Fig. 6 is a view illustrating the overall operation of the second 10 embodiment when an incoming signal from the PBX is a group call.
12 Referring now to Fig. 1, ~here is shown a wide area cordless 3 telephone system embodying the present invention. The whole area of 4 the system is divided into service areas 6. Only two service areas 61 and 15 62 are shown for purposes of simp!icity. Corresponding to service 16 areas, the whole system is divided into subsystems, each comprising a 7 radio control unit 3, access units 4 and cordless stations 5. In the 18 illustrated embodiment, radio control units 31 and 32 are respectively 19 associated with service areas 61 and 62 and connected to line terminals 20 of a private branch exchange 2 to which ordinary telephones 7 may 21 also be connected. The PBX is in turn connected through exchange 22 lines to the public switched telephone network 1. Calls between stations 23 belonging to different service areas are made via the PBX.
24 Cordless stations 5 are divided into groups corresponding to servke 25 areas 61 and 62. Access units 4 are likewise divided into groups 26 corresponding to service areas 6, the access units of each group being 27 located at strategic poin~s of the own service area. For convenience of 28 system description, each service area has as many cordless stations 51 .
,- ' . . - ~ .
, '~
- 5k as there are access units 41 ~ 4k. Access units 4 are connected to 2 the corresponding radio control unit 3 to establish two-way radio 3 channels to cordless stations 51 through Sk which belong to the same 4 service area. Incoming calls from the PBX are made on a per individuai s (or per station) basis or on a per group (or per area) basis. The term 6 "group" in this specification refers to the cordless stations belonging to 7 each service area. In response to a group-based incoming call (or 8 simply, a group call), ringing signals are transmitted to all cordless 9 stations of each service area to alert the users of the same group.
10 Whereas, in response to an individual call, only one uniquely addressed 11 cordless station is alerted in a manner known in the art.
12 A service console unit 8 is connected to radio control units 3 for 13 setting various systern parameters to configure a wide-area cordless 14 telephone system that is particularly tailored to the needs of the users.
Each subsystem has a fuil-duplex control channel and several full-16 duplex speech channels. The control channel is used for exchanging 17 control signals during call setup periods before connections are 18 established on a speech channel. In a well known manner, each of the 19 access units and cordless stations is provided with a radio transceiver 20 and frequency synthesizers for establishing a connection between them 21 in response to a channel switching signal using a microprocessor-based 22 controller. Similarly, each radio control unit includes a microprocessor-23 based controller for providing overall subsystem control.
24 The signal exchanged between each radio control unit and each 25 access unit and the signal exchanged between each access unit and 26 each cordless station are transrnitted as a 214-bit packet containing a 27 preamble, a frame sync, a group identifier, check bits, a control field 2 8 and a data field. The control field indicates the type of call (individual or .., ~.
group) and a channel identifier. The data field contains a called station 2 address number, a group address number, a channel identifier, and a 3 pairing identifier which will be used in the second embodiment of this 4 invention for pairing an access unit and a cordless during an incoming S group call.
6 In Figs. 2A, 2B and 2C, routines of programmed instructions are 7 iilustrated for processing an incoming individual call and an incoming 8 group cali from the PBX according to a first embodiment of the present g invention, with Figs. 2A, 2B and 2C corresponding to the instructions performed by the microprocessor-based controllers of radio control unit 11 3, access unit 4 and cordless station 5, respectively.
12 In Fig. 2A, the program execution of each radio control unit starts 13 with decision step 21 which determines whether the incoming call is an 14 individual or group call. If decision is made in favor of an individual call, exit is to operations step 22 which directs the sending of a standby 16 signal which is a command signal for tuning a received access unit or 7 cordless station to the control channel. This standby signal is sent to 18 one of the associated access units to cause it to switch to the specified 19 control channel for readying to receive a forthcoming alert signal. Exit 20 then is to decision step 23 which checks to see if an acknowledgment 21 signal is returned from the access unit. If there is none, control repeats 22 step ~2 to retransmi~ the standby signal. If the answer is affirmative in 23 step 23, operations step 24 is executed hy sending an alert signal to that 24 access unit, containing the address, or identifier of the called station. If 2 5 an acknowledgment is received from the access unit (step 25) in 26 response to this alert signal, control moves to step 26 to determine if an 27 "alert response" signal is returned from the access unit, indicating that 28 the alert signal has been relayed through the access unit and received - , .
,'' , by the called station to invoke a series of preliminary actions necessary 2 for it to accept the call. Control then goes to step 27 to check to see if 3 an "end-of-connection" signal is returned from the access unit, indicating 4 that the called station is ready to accept the incoming call. If it is, control S advances to step 28 to send a ringing signal to the access unit to alert 6 the user. If a negative decision is made in each of steps 25, 26 and 27, 7 control returns to step 24 to retransmit the alert signal. When the called 8 station goes off hook, an off-hook signal is transmitted from the called 9 station and relayed by the access unit to the radio control unit. Decision 10 step 29 is provided to check to see if the off-hook signal is received from 11 the access unit. If the answer is affirmative, control moves to the end of 12 the incoming call processing routine and enters a talking routine, not 1 3 shown.
14 If the incoming call is a group call, step 30 is executed by setting a 15 variable i to one. Exit then is to step 31 which directs the sending of a 16 standby signal to access unit 4j to cause it to switch its transceiver to the17 radio control channel of the subsystem in order to make it quickly 18 respond to a signal from the RCU and send a copy of it to cordless 19 stations. If an acknowiedgment signal is returned fro access unit 4j (step 20 32), controi advances to step 33 which directs the sending of an alert 21 signal to access unit 4j, containing the address ~ one of the cordless 22 stations of the called group. I~ an acknowledgment signal is returned 23 from access unit 4j (step 34), control proceeds to step 35 to check to see 24 if an alert response signal is received. This signal corresponds to the 25 alert response of step 26. As will be understood as the description 26 proceeds, the addressed cordless station responds to the aler~ signal 27 and returns an alert response containing in it the address of the own 2 8 station and invokes a series of preliminary actions to receive the call. !f ~, . .
.. . .
~, , the answer is affirmative in step 35, end-of-connection check is made 2 (step 36). If the connection is established, control moves to step 37 to 3 increment variable i by one and proceeds to step 38 to check to see if i 4 = k. If the answer is negative, control returns to step 31 to repeat the s process so that the next cordless station is alerted and a connection is 6 established to it. By repeating ~he process until i = k, all cordless stations 7 of the called group are alerted and connections established.
8 Control now exits the loop and enter3 step 40 to reset variable i to 9 one to initiate a ringing sequence. A ringing signal is sent to access unit 1~ 4j (step 41), and variable i is incremented by one (step 42) and checked 11 against the value k (step 43) to see if there is a match or mismatch 12 therebetNeen. If i is smaller than k, steps 41 and 42 are repeated so that 13 ringing signals are successively sent to access units 41 through 4k and 14 the users of all stations of the called group are alerted in rapid 15 succession. If one of the users answers the group call, an off-hook 16 signal is sent from that user station, containing in it the address of the 17 station, and relayed through the associated access unit and received by 18 the radio control unit (step 44). Exit then is to step 45 which directs the 1 9 sending of ring trip signals to all access units other than the unit from 20 which the off-hook signal has been received.
21 In Fig. 2e, the program execution of each access unit begins with 22 decision step 51 which checks to see if a standby signal is received from 2 3 the associated radio control unit. If it is, control exits to step 52 to tune its 24 transceiver to the control channel and returns an acknowledgrnent signal 2s to the RCU (step 53). Exit then is to step 54 which checks to see if an 26 alert signal is received frorn the RCU. If the answer is affirmative, control27 exits to step 55 to return an acknowledgement signal to the RCU and 28 goes to step 56 to send an alert signal to the associated cordless station.
.
Exit then is to step 57 to check to see if there is an alert response from 2 the cordless station. If there is one, control moves to step 58 to return 3 an alert response to the RCU and sends a speech channel identifier to 4 the cordless station (step ~9). Control proceeds to step 60 to tune to a speech channel specified by the channel identifier, and goes to step 61 6 to determine if there is an end-of switching signal from the cordless 7 station signifying that it has switched to the specified speech channel. If8 the answer is negative, control exits to step 70 to switch the transceiver 9 of the access unit to the control channel, and control returns to step 51.
If the answer is affirmative, control exits to step 62 to check to see if an interference check signal is received from the associated cs rdless station 12 indicating that no interference occurs on the specified speech channel.
13 If the answer is negative, control exits to step 70, and if affirmative, it14 moves to step 63 to return an end-of-connection signal to the RCU
indicating that a call attempt to that cordiess station is successful. On 16 receiving this end-of-connection signal, the radio control unit sends a 17 ringing signal to the access unit wh;ch checks it (step 64) and 1~ regenerates it (step 65) for transmission to the associated cordless 19 station. If an off-hook signal is received from the cordless station (step 66), the access unit returns an off-hook signal to the RCU (step 67). If no 21 off-hook signal is received, control moves to step 68 to check for the 22 presence of a ring trip signal from the RCU. If there is one, a ring trip 23 signal is regenerated by the access uni~ and transmitted to the cordless 24 station (step 69).
In Fig. 2C, the program execution of each cordless station begins 2 6 with decision step 71 which checks to see if there is an alert signal from 27 the associated access unit. If ~here is one, control moves to step 72 to 2 8 return an alert response to the RCU. Exit then is to step 73 to check for the presence of a speeth channel identifier from the access unit. If there 2 is one, control exits to step 74 to tune its transceiver to a speech channel 3 specified by the channel identifier. An end-of-switching signal is sent to 4 the access unit (step 75) and interference is checked (step 76). If no interfering signal is present on the speech channel, the cordless station 6 transmits an interference check signal to the access unit (step 77). If 7 interference exists, control advances to step 84 to switch its transceiver to 8 the control channel and returns to step 71. Following the transmission of 9 the interference check signal, the cordless station waits for the receptionof a ringing signal (step 7~) and activates its ringer (step 7~) in response 11 to it. If the cordless station goes off (step 80), an off-hook signal is sent 1 2 to the access unit (step 81), containing in it the station address. If the 13 ringing signal goes unnoticed by the station, control exits to step 82 to 14 check for the presence of a ring trip signal. If the answer is negative, control returns to step 80, and if the answer is affirmative, control 16 proceeds to step 83 to deactivate the ringer and exits to step 84 to 17 switch the station transceiver to the control channel.
18 The overall operation of the first embodiment of the present 19 invention will be fully understood with reference to Figs. 3 and 4 in which operational sequences for individuai and group calls are 21 respectively illustrated.
Z2 If an incoming call received by a radio control unit from the PBX is 2 3 an individual cali (Fig. 3), a standby signal 200 is transmitted from the 24 RCU to an access unit which returns an acknowledgment signal 201 to 2 5 the RCU. The latter then sends an alert signal 202 to the access unit 2~ which returns an acknowledgment 203 and sends an alert signal 204 to 27 a called sta~ion, containing in it the adclress of the called station. The 28 called station recognizes that an incoming call is forthcoming and , re~urns an alert response 205 to the access unit, containing in it the own 2 address number. The access unit returns an alert signal 207 to the RCU
3 and sends back a speech channei identifier 206 to the called station to 4 cause it to switch to a specified speech channel. When this switching is S complete, the called station sends an end-of-switching signal 208 to the 6 access unit and provides an interference check. If no interference 7 occurs, it sends an interference check signal 209 to the access unit, 8 which responds to it by retuming an end-of-connection signal 210 to the 9 RCU. A ringing signal 211 is then ~ransmitted from the RCU to the 10 access unit which relays it as a signal 212 to the called station.
11 If the incoming call from the PBX is a group call (Fig. 4), a standby 1 2 signal 300 is sent from the RCU to an access unit #1, which returns an 13 acknowledgment signal 301 to it and switches its transceiver to the 14 control channel. The RCU then sends an alert signal 302 to access unit 15 #1, which sends a copy 304 of the alert signal to a cordless station #1.
16 Following the reception of acknowiedgment signal 303, the RCU sends a 17 standby signal to access unit #2, which tunes its transceiver to the 18 control channei and returns an acknowledgment signal 3Q6 to the RCU.
19 On the other hand, cordless station #1 returns an alert response 307 to 20 access unit #1, containing in it the address number of station #1. A copy 21 308 of the alert signal is returned from access unit #1 to the RCU, and a 22 speech channel identifier 309 is sent ~o station #1. S~ation #1 switches its 23 transceiver from the control channel to a speech channel specified by 24 the channel identifier and returns an end-of-switching signal 310 to 2 s access unit #1, followed by an interference check signal 31 1 if no 26 interference is detected on the speech channel. Access unit #l 27 responds to interference check signal 311 by returning an end-of-28 connection signal 312 to the~RCU.
, -:
' The transmission of alert signal 302 marks the beginning of a 2 sequence 1 for the exchanging of signals between access unit #1 and 3 station #1 and the reception of end-of-connection signal 312 marks the 4 end of the sequence 1. Similar events occur during a sequence 2 for the S exchanging of signals between access unit #2 and cordless station #2 6 except for the transmission of a standby signal to another access unit if 7 access unit #2 is the last one. Thus, similar sequences are repeated as 8 many times as there are access units, so that the ringers of all cordless 9 stations of the called group are activated ~o alert all users of the called 1 û group.
11 At the end of sequence 2, a ringing signals 313 and 314 are 12 successively sent from the RCU to access units #1 and #2, respectively, 3 and relayed as copies 315 and 316 of the ringing signals to stations #1 14 and ~2, respectively. If station #1 goes off hook, it sends an off-hook 15 signal 317 to access unit #1 and a copy 318 of this signal is returned 16 from access unit #1 to the RCU. In response to the off-hook signa3 318, 17 the RCU sends a ring trip signal 319 to access unit #2, which relays a 18 copy 320 of the ring trip signal 319 to station #2 to deactivate its ringer.
19 It is seen that such ring trip signals will be sent to other cordless stations if 20 more than two cordless stations are provided.
21 A second embodiment of the present invention is shown in Figs. SA, 22 SBandSC.
2 3 In Fig. 5A, the program execution of each radio control unit starts 24 with decision step 101 which determines whether the incoming call is an individual or group call. If an individual call is received, exit is to 26 operations step 22 of Fig. 2A to perform instructions shown therein in a 27 manner as described above. If a group call is received, control exits to 2 8 step 102 to send a group alert signal to one of the access units. This , .
NE-31 ~
group alert signal contains a plurality of pairing identifiers indicating 2 access units and cordless stations which establish a channel 3 therebetween when responding to an incoming group call. As will be 4 described, the access unit receiving the group alert signal from the RCU
S sends a copy of this signal to all cordless stations of the called group.
6 Exit then is to decision step to check for the presence of an 7 acknowledgment signal from that access unit. If the answer is 8 affirmative, control goes to step 104 to successively send group standby 9 signals to all access units other than one to which the group standby 10 signal has been sent. Each of these group standby signals contains a different pairing identifier. Following a timeout period (step 105) in 12 which the RCU checks for the presence of acknowledgment signals from 13 all the receiving access units, control proceeds to step 106 to check for 14 the presence of an end-of-connection signal from one of the access 1 s units. If there is one, a ringing signai is sent to that access unit (step 107).
16 Control proceeds to step 108 to check to see if the ringing signal is sent 17 to all access units to which the group standby signals have been 18 transmitted. If the answer is negative, control repeats the execution of 19 steps 106 and 107, and if the answer is affirmative, it proceeds to step 1û9 to check for the presence of an off-hook signal. If there is one, 21 control advances to operations step 110 which directs the sending of 22 ring trip signals to the access units other than the one from which the 23 off-hook signal has been received.
24 In Fig. 5B, the program execution of each access unit starts with decision step 111 which determines which signal the access unit has 2 6 received. If the signal is indicative of individual cal, controi moves to step 27 112 to return an acknowledgment signal to the RCU. An aiert signal 2 8 containing a called station address is sent to the stations (step 113). If an - ~-,, - ~
,, ., ~ ,~
: ~ ;
alert response is no~ received within a specified timeout period ~step 2 114), control returns to step 111 to repeat the process.
3 If the signal received from the RCU is a group alert signal, control 4 exits to step 128 to return an acknowledgment signal to the RCU and s moves to step 129 to send a group alert signal containing a different 6 pairing identifier to each cordless station of the called group, and returns 7 tostep111.
8 If the signal received from the RCU is a group standby signal, exit 9 then is to step 130 to return an acknowledgment signal and proceeds to 0 step 131 to store the pairing identifier contained in the received group t 1 standby signal. Exit then is to step 132 to check for the presence of a 12 group alert response signal from a cordless station, containing a pairing 3 identifier. If there is one, exit is to step 133 in which the pairing identifier 14 received from the cordiess station is compared with the pairing identifier received from the RCU to detect a match or mismatch therebetween. If 16 a mismatch is detected, control returns to step 132 to repeat the 1 7 process.
1 8 If the answer is affirmative in step 114 or a makh is detected in step 19 133, exit then is to step 115 to send a speech channel identifier to the access unit that has retumed the individual or group alert signal, 21 followed by step 116 to tune to a speech channel specified by the 22 channel identifier. An alert response signal is then sent to the RCU (step 23 117) and the presence of an end-of-switching signal from the cordless 24 station is checked (step 118). If there is one, control proceeds to step 119 to check for the presence of an interference check signal from the 2 6 station. If there is one, control goes to step 120 to return an end-of-27 connection signal to the RCU. Control then checks for the presence of a 28 ringing signal from the RCU (step 121 ) and moves to step 122 to send a ringing signal to the cordless station. The presence of an off-hook 2 signal frorn the station is then checked (step 123). If the answer is 3 affirrnative, control returns an off-hook signal to the RCU (step 124~, and 4 if negative, control proceeds to step 12~ to check to see if a ring trip 5 signal is received from the RCU. If it is, control proceeds to step 126 to 6 send a ring trip signal to the cordless station, and goes to step 127 to 7 switch the access unit to the control channel. Following the execution of 8 step 127, control returns to step 111. If negative decision is made in 9 each of steps 118, 119 and 121, control exits to step 127, and if negative 10 decision is made in step 125, control returns to step 123.
11 In Fig. SC, the program execution of each cordless station starts with 2 decision step 141 which determines if the station has received an 13 individual alert signal or a group alert signal. If the received signal is an14 individual alert signal, control exits to step 14~ to return an alert response 15 signal to the access uni~, and control proceeds to step 146.
16 If the receive signal is a group alert signal, step 143 is executed by 17 storing one of the pairing identifiers contained in the received group 18 alert signal which specifies the own cordless station, and control 1 9 executes step 144 by introducing a delay period to wait for the 20 transmission of all group standby signals from the RCU to the access 21 units. Exit then is to step 145 to retrieve the stored pairing identifier and22 return a group alert response signal containing the retrieved pairing 23 identifier to be received by the address unit which has received the 24 same pairing identifier from the RCU. The timeout period specified in 2s s~ep 144 of each cordless station differs from the timeout period each of 26 the other cordless stations so that group alert response signals are 27 transmitted successively from different cordiess stations. Control then 28 proceeds to step 746 to check for the presence of a speech channel identifier from the access unit indicated by the pairing identifier. If this 2 speech identifier is not received by the station within a specified period,3 control returns to step 141. If it is, control exits to step 147 to switch the 4 station transceiver to a speech channel specified by the channel s identifier, and an end-of-switching signal is then sent to the access unit 6 (step 148). Interference check is made on the speech channel (step 7 149). If no interference is detected,-control proceeds to step 148 to send 8 an interference check signal to the access unit. Control proceeds to step -9 151 to check for the presence of a ringing signal from the access unit. If there is one, the ringer is activated (step 152), and control moves ahead 1 1 to step 153 to check for an off-hook condition. If the user answers the 2 call, control exits to step 153 to send an off-hook signal to the access 13 unit. If the off-hook state is not detected within a specified timeout 14 period, control goes to step 154 to check to see if a ring trip signal is received from the access unit. If it is, the ringer is deactivated (step 156 1 6 and control moves to step 157. If interference is detected in step 149, 17 step 157 is executed.
1~ The overall operation of the second embodiment during the 19 individual station cail mode is identical to that of the first embodiment.
The overall operation of the second embodiment during the group 21 call mode will be described below with reference to Fig. 6.
22 When a group alert signal is received from the PBX, a radio eontrol 2 3 unit sends a copy 401 of it to access unit ~t1, which re~urns an 24 acknowledgment signal 403 to the RCU and sends a group alert signal 2 s 402 ~o ail cordless stations, containing in it a first pairing identifier 26 indicating the formation of a pair with address unit #2 and cordless 27 station #1 and a second pairing identifier indicating the formation of a 28 second pair with address unit #3 and cordless station #2. The RCU then successively transmits a group standby signal 404 containing the first 2 pairing identifier to access unit #2 and a group standby signal 405 3 containing the second pairing identifier to access unit #3.
4 Acknowledgment signals 406 and 407 are returned to the RCU from s access units #2 and #3, respectively. At the end of the timeout period 6 (step 144, Fig. 5C), cordless station ~t1 sends a group alert response 7 signal 408 containing the first pairing identifier. This signal is received by8 access unit #2 since the pairing identifier contained in it matches the 9 pairing identifier contained in the group standby signal 404 (step 133, 10 Fig. SB). Access unit #2 returns a copy 409 of group alert response 1 1 signal 408 and sends a speech channel identifier 410 to cordless station 12 #1 of the same pair. The laKer switches its transceiver to a speech 13 channel specified by the channel identifier, sends an end-of-switching 14 signal 411 to access unit #2, provides an interFerence check and sends 15 an interference check siynal 412 to access unit #2. Access unit #~ then 16 returns an end-of-connection signal 413 to the RCU.
16 If the receive signal is a group alert signal, step 143 is executed by 17 storing one of the pairing identifiers contained in the received group 18 alert signal which specifies the own cordless station, and control 1 9 executes step 144 by introducing a delay period to wait for the 20 transmission of all group standby signals from the RCU to the access 21 units. Exit then is to step 145 to retrieve the stored pairing identifier and22 return a group alert response signal containing the retrieved pairing 23 identifier to be received by the address unit which has received the 24 same pairing identifier from the RCU. The timeout period specified in 2s s~ep 144 of each cordless station differs from the timeout period each of 26 the other cordless stations so that group alert response signals are 27 transmitted successively from different cordiess stations. Control then 28 proceeds to step 746 to check for the presence of a speech channel identifier from the access unit indicated by the pairing identifier. If this 2 speech identifier is not received by the station within a specified period,3 control returns to step 141. If it is, control exits to step 147 to switch the 4 station transceiver to a speech channel specified by the channel s identifier, and an end-of-switching signal is then sent to the access unit 6 (step 148). Interference check is made on the speech channel (step 7 149). If no interference is detected,-control proceeds to step 148 to send 8 an interference check signal to the access unit. Control proceeds to step -9 151 to check for the presence of a ringing signal from the access unit. If there is one, the ringer is activated (step 152), and control moves ahead 1 1 to step 153 to check for an off-hook condition. If the user answers the 2 call, control exits to step 153 to send an off-hook signal to the access 13 unit. If the off-hook state is not detected within a specified timeout 14 period, control goes to step 154 to check to see if a ring trip signal is received from the access unit. If it is, the ringer is deactivated (step 156 1 6 and control moves to step 157. If interference is detected in step 149, 17 step 157 is executed.
1~ The overall operation of the second embodiment during the 19 individual station cail mode is identical to that of the first embodiment.
The overall operation of the second embodiment during the group 21 call mode will be described below with reference to Fig. 6.
22 When a group alert signal is received from the PBX, a radio eontrol 2 3 unit sends a copy 401 of it to access unit ~t1, which re~urns an 24 acknowledgment signal 403 to the RCU and sends a group alert signal 2 s 402 ~o ail cordless stations, containing in it a first pairing identifier 26 indicating the formation of a pair with address unit #2 and cordless 27 station #1 and a second pairing identifier indicating the formation of a 28 second pair with address unit #3 and cordless station #2. The RCU then successively transmits a group standby signal 404 containing the first 2 pairing identifier to access unit #2 and a group standby signal 405 3 containing the second pairing identifier to access unit #3.
4 Acknowledgment signals 406 and 407 are returned to the RCU from s access units #2 and #3, respectively. At the end of the timeout period 6 (step 144, Fig. 5C), cordless station ~t1 sends a group alert response 7 signal 408 containing the first pairing identifier. This signal is received by8 access unit #2 since the pairing identifier contained in it matches the 9 pairing identifier contained in the group standby signal 404 (step 133, 10 Fig. SB). Access unit #2 returns a copy 409 of group alert response 1 1 signal 408 and sends a speech channel identifier 410 to cordless station 12 #1 of the same pair. The laKer switches its transceiver to a speech 13 channel specified by the channel identifier, sends an end-of-switching 14 signal 411 to access unit #2, provides an interFerence check and sends 15 an interference check siynal 412 to access unit #2. Access unit #~ then 16 returns an end-of-connection signal 413 to the RCU.
17 The reception of group alert response 409 by the RCU marks the 18 beginning of a sequence 1 and the reception of end-of-connection 19 signal 413 marks the end of sequence 1. Sequence 2 similar to 20 sequence 1 begins with the reception of a group alert response signal 21 415 by the RCU from access unit ~3 in which there is a match between 22 the pairing identifier received from station #2 and the one contained in 23 group standby signal 405. An end-of-switching signal 417 and an 24 interference check signal 418 are successively sent from station #3 to 2s access unit #3 of the same pair, which returns an end-of-connection 26 signal 419 to the RCU at the end of sequence 2.
27 Ringing signals 420 and 421 are successively transmitted from the 28 RCU to access units #2 and #3, respectively, resulting in the transmission of copies 422 and 423 of ringing signals 420,421, to cordless stations #1 2 and ~2, respectively. If station #1 goes off hook, it sends an off-hook 3 signal 424 to access unit ~2, which returns a copy 425 of this off-hook 4 signal to the RCU. In response to the off-hook signal 42~, the RCU
sends a ring trip signal 476 to access unit $t3, which sends a copy 427 of 6 ring trip signal 426 to cordless station #3.
7 The foregoing description shows only preferred embodiments of 8 the present invention. Various modifications are apparent to those 9 skilled in the art without departing from the scope of the present 0 invention which is only limited by the appended claims. Therefore, the 11 embodiments shown and described are only illustrative, not restrictive.
27 Ringing signals 420 and 421 are successively transmitted from the 28 RCU to access units #2 and #3, respectively, resulting in the transmission of copies 422 and 423 of ringing signals 420,421, to cordless stations #1 2 and ~2, respectively. If station #1 goes off hook, it sends an off-hook 3 signal 424 to access unit ~2, which returns a copy 425 of this off-hook 4 signal to the RCU. In response to the off-hook signal 42~, the RCU
sends a ring trip signal 476 to access unit $t3, which sends a copy 427 of 6 ring trip signal 426 to cordless station #3.
7 The foregoing description shows only preferred embodiments of 8 the present invention. Various modifications are apparent to those 9 skilled in the art without departing from the scope of the present 0 invention which is only limited by the appended claims. Therefore, the 11 embodiments shown and described are only illustrative, not restrictive.
Claims (8)
1. A wide area cordless telephone system for covering a plurality of service areas in each of which a plurality of cordless stations are located, comprising:
control means connected to a telephone network for generating a group-call signal in response to an incoming call from the telephone network; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said group-call signal for successively transmitting speech-channel identifiers to said cordless stations through said control channel and transmitting ringing signals respectively to said cordless stations through a plurality of said speech channels which are specified by said successively transmitted speech-channel identifiers.
control means connected to a telephone network for generating a group-call signal in response to an incoming call from the telephone network; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said group-call signal for successively transmitting speech-channel identifiers to said cordless stations through said control channel and transmitting ringing signals respectively to said cordless stations through a plurality of said speech channels which are specified by said successively transmitted speech-channel identifiers.
2. A wide area cordless telephone system as claimed in claim 1, wherein each of said cordless stations transmits an off-hook signal through the respective speech channel to said control means via one of said access units if an off hook condition occurs following reception of said ringing signals, said control means transmitting ring trip signals through said access units to the cordless stations other than the cordless station which transmitted said off-hook signal.
3. A wide area cordless telephone system for covering a plurality of service areas in each of which a plurality of cordless stations are located, comprising:
control means connected to a telephone network for generating an alert signal containing a plurality of pairing identifiers in response to an incoming call from the telephone network, and successively generating standby signals each containing a different one of said pairing identifiers; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, a specified one of said access units being responsive to said alert signal for transmitting a copy of said alert signal to each of said cordless stations through said control channel and causing said cordless stations to successively return respective ones of said pairing identifiers through said control channel, said access units being respectively responsive to said standby signals for respectively storing a pairing identifier contained in a respective one of said standby signals, each of said access units being responsive to one of the pairing identifiers from said cordless stations for transmitting a speech-channel identifier to the cordless station specified by the stored pairing identifier through said control channel if said one of the pairing identifiers from said cordless stations is identical to the stored pairing identifier and transmitting a ringing signal to said specified cordless station through a said speech channel specified by said transmitted speech-channel identifier.
control means connected to a telephone network for generating an alert signal containing a plurality of pairing identifiers in response to an incoming call from the telephone network, and successively generating standby signals each containing a different one of said pairing identifiers; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, a specified one of said access units being responsive to said alert signal for transmitting a copy of said alert signal to each of said cordless stations through said control channel and causing said cordless stations to successively return respective ones of said pairing identifiers through said control channel, said access units being respectively responsive to said standby signals for respectively storing a pairing identifier contained in a respective one of said standby signals, each of said access units being responsive to one of the pairing identifiers from said cordless stations for transmitting a speech-channel identifier to the cordless station specified by the stored pairing identifier through said control channel if said one of the pairing identifiers from said cordless stations is identical to the stored pairing identifier and transmitting a ringing signal to said specified cordless station through a said speech channel specified by said transmitted speech-channel identifier.
4. A wide area cordless telephone system as claimed in claim 3, wherein each of said cordless stations transmits an off-hook signal through the respective speech channel to said control means via one of said access units if an off hook condition occurs following reception of said ringing signal, said control means transmitting ring trip signals through said access units to the cordless stations other than the cordless station which transmitted said off-hook signal.
5. A wide area cordless telephone system for covering a plurality of service areas in each of which a plurality of cordless stations are located, comprising:
control means connected to a telephone network for generating an individual-call signal when an incoming call from said network is an individual call directed to one of the cordless stations and generating a group-call signal when said incoming call is a group call directed to all cordless stations located in a same service area; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said individual-call signal for transmitting a speech-channel identifier to one of the cordless stations through said control channel and transmitting a ringing signal through a speech channel specified by said speech-channel identifier, and responsive to said group-call signal for successively transmitting speech-channel identifiers to said cordless stations through said control channel and transmitting group ringing signals respectively to said cordless stations through a plurality of said speech channels which are specified by said successively transmitted speech-channel identifiers.
control means connected to a telephone network for generating an individual-call signal when an incoming call from said network is an individual call directed to one of the cordless stations and generating a group-call signal when said incoming call is a group call directed to all cordless stations located in a same service area; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said individual-call signal for transmitting a speech-channel identifier to one of the cordless stations through said control channel and transmitting a ringing signal through a speech channel specified by said speech-channel identifier, and responsive to said group-call signal for successively transmitting speech-channel identifiers to said cordless stations through said control channel and transmitting group ringing signals respectively to said cordless stations through a plurality of said speech channels which are specified by said successively transmitted speech-channel identifiers.
6. A wide area cordless telephone system as claimed in claim 5, wherein each of said cordless stations transmits an off-hook signal through the respective speech channel to said control means via one of said access units if an off hook condition occurs following reception of said group ringing signals, said control means transmitting ring trip signals through said access units to the cordless stations other than the cordless station which transmitted said off-hook signal.
7. A wide area cordless telephone system for covering a plurality of service areas in each of which a plurality of cordless stations are located, comprising:
control means connected to a telephone network for generating an individual-call signal when an incoming call from said network is an individual call directed to one of the cordless stations and generating a group alert signal containing a plurality of pairing identifiers when said incoming call is a group call directed to all cordless stations located in a same service area, and successively generating group standby signals each containing a different one of said pairing identifiers; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said individual-call signal for transmitting a speech-channel identifier to one of the cordless stations through said control channel and transmitting a ringing signal through a speech channel specified by said speech-channel identifier, a specified one of said access units being responsive to said group alert signal for transmitting a copy of said group alert signal to each of said cordless stations through said control channel and causing said cordless stations to successively return respective ones of said pairing identifiers through said control channel, and said access units being respectively responsive to said group standby signals for respectively storing a pairing identifier contained in a respective one of said group standby signals, each of said access units being responsive to one of the pairing identifiers from said cordless stations for transmitting a speech-channel identifier to the cordless station specified by the stored pairing identifier through said control channel if said one of the pairing identifiers from said cordless stations is identical to the stored pairing identifier and transmitting a group ringing signal to said specified cordless station through a said speech channel specified by said transmitted speech-channel identifier.
control means connected to a telephone network for generating an individual-call signal when an incoming call from said network is an individual call directed to one of the cordless stations and generating a group alert signal containing a plurality of pairing identifiers when said incoming call is a group call directed to all cordless stations located in a same service area, and successively generating group standby signals each containing a different one of said pairing identifiers; and a plurality of access units divided into groups corresponding respectively to said service areas, the access units of each group being located in the corresponding service area for establishing a radio control channel and a plurality of radio speech channels with the cordless stations located in the same service area as said access units, said access units being responsive to said individual-call signal for transmitting a speech-channel identifier to one of the cordless stations through said control channel and transmitting a ringing signal through a speech channel specified by said speech-channel identifier, a specified one of said access units being responsive to said group alert signal for transmitting a copy of said group alert signal to each of said cordless stations through said control channel and causing said cordless stations to successively return respective ones of said pairing identifiers through said control channel, and said access units being respectively responsive to said group standby signals for respectively storing a pairing identifier contained in a respective one of said group standby signals, each of said access units being responsive to one of the pairing identifiers from said cordless stations for transmitting a speech-channel identifier to the cordless station specified by the stored pairing identifier through said control channel if said one of the pairing identifiers from said cordless stations is identical to the stored pairing identifier and transmitting a group ringing signal to said specified cordless station through a said speech channel specified by said transmitted speech-channel identifier.
8. A wide area cordless telephone system as claimed in claim 7, wherein each of said cordless stations transmits an off-hook signal through the respective speech channel to said control means via one of said access units if an off hook condition occurs following reception of said group ringing signal, said control means transmitting ring trip signals through said access units to the cordless stations other than the cordless station which transmitted said off-hook signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-30104 | 1990-02-08 | ||
| JP2030104A JP2806591B2 (en) | 1990-02-08 | 1990-02-08 | Receiving method of wireless telephone system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2035962A1 CA2035962A1 (en) | 1991-08-09 |
| CA2035962C true CA2035962C (en) | 1994-11-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035962A Expired - Fee Related CA2035962C (en) | 1990-02-08 | 1991-02-07 | Wide area cordless telephone system capable of receiving incoming group address calls |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5255308A (en) |
| EP (1) | EP0441370B1 (en) |
| JP (1) | JP2806591B2 (en) |
| AU (1) | AU631046B2 (en) |
| CA (1) | CA2035962C (en) |
| DE (1) | DE69132503T2 (en) |
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-
1991
- 1991-02-07 CA CA002035962A patent/CA2035962C/en not_active Expired - Fee Related
- 1991-02-07 DE DE69132503T patent/DE69132503T2/en not_active Expired - Fee Related
- 1991-02-07 EP EP91101677A patent/EP0441370B1/en not_active Expired - Lifetime
- 1991-02-08 AU AU70917/91A patent/AU631046B2/en not_active Ceased
- 1991-02-08 US US07/652,724 patent/US5255308A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU7091791A (en) | 1991-08-15 |
| JP2806591B2 (en) | 1998-09-30 |
| EP0441370B1 (en) | 2001-01-10 |
| EP0441370A3 (en) | 1993-03-31 |
| AU631046B2 (en) | 1992-11-12 |
| DE69132503T2 (en) | 2001-06-13 |
| JPH03234196A (en) | 1991-10-18 |
| US5255308A (en) | 1993-10-19 |
| EP0441370A2 (en) | 1991-08-14 |
| DE69132503D1 (en) | 2001-02-15 |
| CA2035962A1 (en) | 1991-08-09 |
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| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20010207 |