CA1260124A - Subscriber's line switching control system - Google Patents
Subscriber's line switching control systemInfo
- Publication number
- CA1260124A CA1260124A CA000523471A CA523471A CA1260124A CA 1260124 A CA1260124 A CA 1260124A CA 000523471 A CA000523471 A CA 000523471A CA 523471 A CA523471 A CA 523471A CA 1260124 A CA1260124 A CA 1260124A
- Authority
- CA
- Canada
- Prior art keywords
- subscriber
- line
- digital
- channel
- handler
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/12—Arrangements providing for calling or supervisory signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
Abstract
SUBSCRIBER'S LINE SWITCHING CONTROL SYSTEM
ABSTRACT OF THE DISCLOSURE
In this invention, a call control information of a subscriber's line is compiled into a packet form, is transferred via a network of a digital switch board to a signal control device, and digital data is also trans-ferred via the network to a handler. Accordingly, a signal from a digital subscriber is efficiently pro-cessed, and an analog subscriber is also accommodated so that a call control in the same way as for the digital subscriber is made possible for the analog subscriber.
ABSTRACT OF THE DISCLOSURE
In this invention, a call control information of a subscriber's line is compiled into a packet form, is transferred via a network of a digital switch board to a signal control device, and digital data is also trans-ferred via the network to a handler. Accordingly, a signal from a digital subscriber is efficiently pro-cessed, and an analog subscriber is also accommodated so that a call control in the same way as for the digital subscriber is made possible for the analog subscriber.
Description
~L~6~
SUBSCRIBER'S LINE SWITCHING CONTROL SYSTEM
BACKGROUND OF TEE INVENTION
1. Field of the Invention The present invention relates to a subscriber's line switching control system in which, in a digital switching system accommodating a subscriber's line, an efficient switching control can be carried out for both a digital subscriber's line and an analog subscriber's line.
SUBSCRIBER'S LINE SWITCHING CONTROL SYSTEM
BACKGROUND OF TEE INVENTION
1. Field of the Invention The present invention relates to a subscriber's line switching control system in which, in a digital switching system accommodating a subscriber's line, an efficient switching control can be carried out for both a digital subscriber's line and an analog subscriber's line.
2. Description of the Related Arts An analog subscriber's line is usually used as a subscriber's line accommodated in a digital switching system, but because of developments in digital tech-niques, a digital subscriber's line is also used therein, as disclosed in U.S. Patent No. 4,571,721. In this disclosure, the analog subscriber's line and the digital subscriber's line are combined, and thus a satisfactory interface is required.
In a remote line concentrator having a construction in which the digital subscriber's line and the analog subscribex's line are accommodated, a concentrator stage of a part of a master office is set at a remote location, and a connection control is carried out in accordance with switching connection control information from the master office, to process the digital signal in the same way as in a digital switching system.
The interface between the digital subscriber and the switching system is prescribed by the CCITT
(International Telegraph and Telephone Consultative Committee), and therein it is specified that the call control information which controls the low speed digital data and the call information, etc., via the digital subscriber's line from the digital subscriber is sent on the D channel (16 kb/s), and a high speed data including voice information, etc., is sent on the B channel o~
~64 kb/sJ. In the digital subscriber's line, the D channel and the s channel are separated, and the data in the D channel is transferred to a D channel handler.
In such a remote line concentrator, the call control information at the analog subscriber is received via a scan/signal separator, ana the call control information at the digital subscriber is received via the D channel handler. Therefore, there i5 a drawback in that the construction becomes complex because the interfaces of the call control information are different in the analog subscriber and the digital subscriber.
Further, the D channel handler and the scan/
signal separator are centralized, so that the con-struction becomes comparatively large scale. Also, when the ratio between the digital subscriber and the analog subscriber chanyes, a drawback occurs in the ~ channel handler or the scan/signal distributor becomes uneconomicalO
SUMMARY OF THE IN~7ENTION
An object of the present invention is to provide a subscriber's line switching control system having a substantially similar interface condition for both the digital subscriber and the analog subscriber, so as to simplify the construction.
Another object of the present invention is to provide a subscriber's line switching control system having an economical construction, even if the ratio between the digital subscriber and the analog subscriber changes.
For achieving the above-mentioned object, in the present invention, a subscriber's line switching control system comprises a network of a digital switching system which accommodates via a subscriber's line inter~acer one or both of a digital subscriber's line and an analog F 35 subscriber's line; a packet handler which is connected directly to the network and to a signal control device connected in the network, or which is provided in ~ 3 --another office; and a processor which controls the netwGrk according to control information from the signal control d~vice.
Call control information is compiled into a packet orm in the subscriber's line interfacer, the call control information converted to the packet form is transferred via the network to the signal control device, and digital data via the digital subscriber's line is converted via the network to the packet handler.
Further features and advantages of the present invention will be apparent from the ensuing description with reference to the accompanying drawings to which, however, the scope of the invention is in no way limited.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a block diagram of one example of a conventional remote line concentrator in which a digital subscriber's line and an analog subscriber's line are accommodated;
Figs. 2A and 2~ show a formation of a digital subscriber's line and a format of D channel data pre-scribed by the CCITT;
Fig. 3 is a block diagram showing a principle of the present invention;
Fig. 4 is a block diagram of one embodiment of a remote line concentrator in which a digital subscriber's line and an analog subscriber's line are accommodated;
Fig. 5 is a block diagram of one embodiment of D channel handler shown in Fig. 4;
Fig. 6 is a diagram explaining a function of the D channel handler shown in Fig. 5; and Fig. 7 is a block diagram of one embodiment o~ a signal control device shown in Fig. 4.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
A conventional remote line concentrator in which the digital subscriber's line and the analog subscriber's line are accommodated has, for example, a construction as shown in Fig. 1. In Fig. 1, la ~ ln are digital - ~1.26~
subscribers, 2a ~ 2n are analog subscribers t 3a ~ 3n are digital subscriber's lines, 4a ~ 4n are analog sub-scriber's lines, 5a ~ 5n are digital subscriber's line circuits (DLC), 6a ~ 6n are analog subscriber's line circuits (SLC), 7 is a D channel handler (DH), ~ is a scan/signal distributor (SCN/SD), 9 and 10 are multi-plexing/demultiplexing separators (MPX), 11 is a network (NW), 12 is a processor, and 13 is a packet handler (PH).
In this construction of the remote line, a concen-trator stage of a part of a master office (not shown inthe drawing) is set in a remote place, and a connection control is carried out in accordance with switching connection control information from the master office so that the network 11 processes the digital signals in the same way as in a digital switching system.
An interface between the digital subscriber and the switching system is, as shown in Fig. 2A, prescribed by the CCITT, and it is specified therein that the call control information which controls the low speed digital data and the call information, etc., via the digital subscrîber's line 3a ~ 3n from the digital subscriber la ~ ln is sent on the D channel (16 kb/s), and high speed data including voice information, etc., is sent on the B channel (6~ kb/s). In the digital subscriber's line circuit 5a ~ 5n, the D channel and the B channel -- are separated, and the da~a on the D channel is trans-ferred to the D channel handler 7.
The data on the B channel is multiplexed in the multiplexing/demultiplexing device 9, and is sent via the network 11 to the master office (not shown in the drawing). The data received via the master office is separated at the network 11 in the multiplexing/
demultiplexing device 9, and is sent via the digital subscriber's line circuits 5a ~ 5n to the predetermined subscriber la ~ ln.
In the D channel handler 7, the digital data and the call information compiled into packet form are _ 5 _ separated, and accordingly, the separated call control information is transferred to the processor 12, and the digital data is transferred to the packet handler 13.
The packet handler 13 outputs the digital data via the packet switchboard, etc. The processor 12 is used to control the call control information in the network 11. The D channel handler 7 is commonl~ used for all of the digital subscriber's line circuits 5a 5n, even in a construction having a plurality of multiplexingfdemultiplexing devices 9.
The information concerning an on-hook and off-hook, etc., by the subscriber 2a ~ 2n is transferred to the processor 12 by scanning and detecting signals in the analog subscriber's line circuits 6a ~ 6n by the scan/
signal distributor 8, and the processor 12 controls the network 11 accordingly. The analog voice signal is converted to a digital signal by the analog subscriber's circuits 6a ~ 6n, is multiplexed by the multiplexing/
demultiplexing device 10, and is sent via the network 11 to the master office.
The digital voice signal from the master office is separated via the network 11 in the multiplexing/
demultiplexing device 10, is converted to an analog voice signal in the analog subscriber's line circuits 6a ~ 6n, and is sent to the analog subscriber. In this - case, the scan/signal separator 8 is commonly used, even if a plurality of the multiplexing/demultiplexing devices 10 are used.
In the processor 12, the call control information from the analog subscriber is received via the scan/
signal separator 8 and the call control information from the digital subscriber is received via the D channel handler 7. Therefore, it has a drawback in that the construction becomes complex because the interfaces of the call control information are different in the analog subscriber and the digital subscriber.
Further, the D channel handler 7 and the scan/signal ~2601~4 separator 8 are centralized, so that the construction becomes comparatively large scale. Then, when the ratio between the digital subscriber and the analog subscriber changes, a drawback arises in that the D channel handler 7 or the scan/signal distributor 8 becomes uneconomical.
In the subscriber's line switching control system of the present invention, the call control information and the digital data in the D channel are transferred via the network. This will be explained with reference to Fig. 3. In Fig. 3, the digital subscriber's line 21 and the analog subscriber's line 22 are connected to the network 24 of the digital switchboard via the sub-scriber's line interfacer 23 including the subscriber's line circuits or the multiplexing/demultiplexing device, etc. The call control information from the subscriber is compiled into packet form in the subscriber's line interfacer 23, and the call control information in the packet form is transferred via the network 24 to the signal control device 25 r and thus the processor 27 controls the network 24 in accordance with the control information from the signal control device 25. Further, the digital data via the digital subscriber7s line 21 is transferred to the packet handler 26 directly connected to the network 2~, or to a packet handler provided in another office.
The call control information from the diyital subscriber ana the analog subscriber is compiled into packet form in the subscriber's line interfacer 23, and transferred via the network 24 to the signal control device 25, so that similar processes can be carried out for the digital subscriber's line 21 and the analog subscriber7s line 22. ~s the digital data in the form of packet data is also transferred via the network 24, if a packet handler 26 is set in another office, such as the master office, etc., the digital data can be trans-ferred thereto.
Figure 4 is a block diagram of the embodiment of the present invention, and shows the present invention when applied to the remote line concentrator as in the prior art shown in Fig. 1. In Fig. 4, 21a ~ 21n are digital subscribers, 22a ~ 22n are analog subscribers, 29a ~ 29n are digital subscriberls lines, 30a ~ 30n are analog subscriber's lines, 31a ~ 31n are digital sub scriber's line circuits tDLC), 32a ~ 32n are analog subscriber's line circuits (SLC), 32 is a D channel handler ~DH), 33 is a scan/signal distributor (SCN/SD), 34, 35 are multiplexing/demultiplexing separators (MPX), 24 is a network (NW), 27 is a processor which controls the network and other portions, 2~ is a packet handler (PH), and 25 is a signal control device (SIG).
The D channel handler 32 is provided for each multiplexing/ demultiplexing device 34, and the scan and signal distributor 33 is provided for each multiplexing/
demultiplexing device 35. The multiplexing/demulti-plexing devices 34, 35 each carry out the multiplexing and the demultiplexing for, for example, 6~ subscribers.
Therefore, when the number of digital subscribers 21 or analog subscribers 22 is more than 60, additional multiplexing and demultiplexing device 34, 35 are provided at every integral number of 60, and accordingly, a D channel handler 32 or the scan/signal distributor 33 is provided for each additional multiplexing/demulti-plexing device.
The D channel, which is transferred from the digital sllbscriber 21 via the digital subscriber's line 29 to the digital subscriber's line circuit 31 and is separated in the digital subscriber's line circuit 31, is transferred to the D channel handler 32. The call control information is separated in this D channel handler 32 and transferred from the multiplexing/demulti-plexing device 34 via a path ~ shown by the broken - 35 line in the network 24 to the signal control circuit 25, and the call control information is then transferred from the signal control device 23 to the processor 27, -` ~LX~ 4 so that control of the network 24 is carried out. For example, a path ~ in the network 24 is formed by the call control information of the call, and the digital data separated in the D channel handler 32 is transferred 5 from the multiplexing/demultiplexing device 34 via the path ~ shown by broken line in the network 24 to the packet handler 26~
The data of the B channel is sent from the digital subscriber's circuit 31 via the multiplexing/demulti-plexing device 34 and the network 24 to the master officeO The data of the B channel from the master office side is supplied via the network 24 to the multiplexing/demultiplexing device 34, where it is separated and synthesized with the data of the D channel in the digital subscriber's line circuit 31, and then transferred via the digital subscriber's line 29 to the digital subscriber 21. As a result, communication between the digital subscribers is established.
The analog subscriber's line circuit 32 is scanned in the scan/signal distributor 33, the call control information of the analog subscriber is detected, the detected call control information is compiled as the packet form and is multiplexed in the multiplexing/de-multiplexing device 35, and is then transferred via the path ~ shown by broken line to the signal control circuit 25. The control information is sent from this signal control circuit 25 to the processor 27 to control the network 2~, and then the line concentrating con-nection for the master office is carried out by the network 24. Subsequently, the voice information from the analog subscriber 22 is converted to a digital signal in the analog subscriber's line circuit 32 and is sent from the multiplexing/ demultiplexing device 35 via the network 24 to the master office. Conversely, the digital voice information from the master office is supplied via the network 24 to the multiplexing/demulti-plexing device 35 to be demultiplexed, convertea to an . g analog signal in the analog subscriber's line circuit 32 and transferred to the analog subscriber 22, and thus communication between the subscribers is established.
The signal control device 25 or the packet handler 26, etc., may be included at the side of the multi-plexing/demultiplexing device 34, 35 in the network 24, and the connection between the subscribers connected in the network 24 can be simply controlled by analyzing the dial information in the processor 27.
Next, the D channel handler 32 and the signal control device 25 will be described in detail. Before that explanation, however, referenc~ is made to the D channel data format shown in Fig. 2B. This format is prescribed in Q921 of the CCITT. In Fig. 2B, F denotes a flag which is fixed binary pattern of 01111110;
A denotes an address field;
C denotes a controlled field which contains a sequence number for error recovery;
N(S) denotes a transmitter send sequence number;
N(R~ denotes a transmitter receive sequence number; and, FCS denotes a frame check sequence generated by a polinominal X15 ~ X12 ~ X5 ~ 1 This is as prescribed in Q921 of the CCITT.
- Figure 5 is a block diagram of the D channel handler. In Fig. 5, 51 is a microprocessor unit (MPU), 52 is a memory (MEM), and 53a ~ 53n, 54, 55 are high level data link controllers (HDLC).
When the D channel handler receives the D-channel data from the subscriber's line, the D-channel data (16 k bit/s) is input to the high level data link controllers 53a ~ 53n. The hardware included in the high level data link controller 53a ~ 53n detects the flag F shown in Fig. 2B and carries out the delimitation of the message unit and checks by using the FCS in the format, and only residual A and C fields and the infor-~x~o~
mation are transferred to the memory 5?~
The microprocessor 51 reads the received data and carries out the following process.
a) In the A-field, there is an identifier of whether it is signalling information or user packet, and the microprocessor unit discriminates which kind it is by that identifier.
If it is signalling information, a further process on the sequence number included in the C-field is made by a D-channel protocol (LAPD. link access procedure D~. When it is a normal signal, it is accepted and the content of the information is sent to the signal control device 25 (SIG).
If it is a user packet, it is transferred to the packet handler 26 (PH).
b) The content of the information sent to the signal control device 25 is added by the processing of the microprocessor unit 51 of the A, C field based on the protocol transferred between the D-channel handler and the signal control device, and it is transferred to the high level data link controller 54. (Flag and FCS
are added in the controller 54 and sent to the signal control device 25.) c) With respect to the packet transferred to the packet handler 25~ only the A-field is converted and transferred to the controller 55. The flag and FCS is added to the A-field and is sent to the packet handler 26.
The proces~ing o~ the data received from the signal control device or the packet handler is carried out is the reverse of that shown above.
The above-mentionea function is graphically shown in Fig. 6.
In Fig. 6, when the data is received from the subscriber, the signalling information and the user packet are sepaxated in the blocks 61a ~ 61n, and are merged when the data is sent to the subscriber. In the ~2603L~L~
LAPD process 62, 63, the data received or sent by the subscriber is data link controlled based on the D-channel link access procedure (LAPD). In the data link con-trol 65, the error recovery process based on the data link control protocol between the signal control device and the D-channel handler is carried out. In practice, a process similar to the LAPD process is used~
Figure 7 is a diagram showing the signal control device. In Fig. 7, 71 is a microprocessor unit ~MPU), 72 is a memory (MEM), 73a ~ 73n are high level data link controllers (HDLC), and 74 is a channel interface controller (CHIC).
In Fig. 7, ~hen the data received from the D channel handler is processed, the data from the D channel handler is input to the controllers 73a ~ 73n, the process explained in the description of Fig. 5 is carried out, and the content of the processed information is transferred via the channel interface controller 74 to the processor 25. When the data is receive~ at the processor 25, a process that is, the reverse of that described above is carried out.
The above embodiment is described iIl the case when the present invention is applied to the line concen-trator, but the present invention can be applied also to a terminal office in which the subscriber's line is connected. Further, this embodiment shows the case when the packet handler 26 is directly connected in the network 24, but it is possible to set the packet handler in another office such as the master office, etc. That is~ there is no restriction of the position at which the packet handler 26 is set.
As mentioned above, in the present invention, the call control information of the subscriber is compiled in packet foxm in the subscriber line interfacer 23, and this call control information is transferred via the network 2q to the signal control circuit 25. The digital data via the digital subscriber's line 21 is 60~2~
transferred via the network 24 to the packet handler 26.
Therefore t both the call control information of the digital subscriber and the call control infoxmation o the analog subscriber, which are compiled in packet form, are transferred to the signal control circuit 25, and therefore, the same control can be carried out for the digital subscriber and for the analog subscriber from the processor 27.
Further, compared to the prior art, the number of cables for transferring the call control information is decreased, and therefore an economical construction can be obtained. Further, the position at which the packet handler 26 is set is not restricted, and when the present invention is applied to a remote line concen-trator device, etc., the packet data may be transferredto the master office via the network 24, and therefore the construction can be made more economical.
Further, the D channel handler 32 and the scan/
signal distributor 33 are provided for the multiplexing/
demultiplexing devices 34, 35, to attain a distributed control construction, and therefore, when the inclusion ratio for the digital subscriber and the analog sub-scriber is changed, a flexible response can be realized.
In a remote line concentrator having a construction in which the digital subscriber's line and the analog subscribex's line are accommodated, a concentrator stage of a part of a master office is set at a remote location, and a connection control is carried out in accordance with switching connection control information from the master office, to process the digital signal in the same way as in a digital switching system.
The interface between the digital subscriber and the switching system is prescribed by the CCITT
(International Telegraph and Telephone Consultative Committee), and therein it is specified that the call control information which controls the low speed digital data and the call information, etc., via the digital subscriber's line from the digital subscriber is sent on the D channel (16 kb/s), and a high speed data including voice information, etc., is sent on the B channel o~
~64 kb/sJ. In the digital subscriber's line, the D channel and the s channel are separated, and the data in the D channel is transferred to a D channel handler.
In such a remote line concentrator, the call control information at the analog subscriber is received via a scan/signal separator, ana the call control information at the digital subscriber is received via the D channel handler. Therefore, there i5 a drawback in that the construction becomes complex because the interfaces of the call control information are different in the analog subscriber and the digital subscriber.
Further, the D channel handler and the scan/
signal separator are centralized, so that the con-struction becomes comparatively large scale. Also, when the ratio between the digital subscriber and the analog subscriber chanyes, a drawback occurs in the ~ channel handler or the scan/signal distributor becomes uneconomicalO
SUMMARY OF THE IN~7ENTION
An object of the present invention is to provide a subscriber's line switching control system having a substantially similar interface condition for both the digital subscriber and the analog subscriber, so as to simplify the construction.
Another object of the present invention is to provide a subscriber's line switching control system having an economical construction, even if the ratio between the digital subscriber and the analog subscriber changes.
For achieving the above-mentioned object, in the present invention, a subscriber's line switching control system comprises a network of a digital switching system which accommodates via a subscriber's line inter~acer one or both of a digital subscriber's line and an analog F 35 subscriber's line; a packet handler which is connected directly to the network and to a signal control device connected in the network, or which is provided in ~ 3 --another office; and a processor which controls the netwGrk according to control information from the signal control d~vice.
Call control information is compiled into a packet orm in the subscriber's line interfacer, the call control information converted to the packet form is transferred via the network to the signal control device, and digital data via the digital subscriber's line is converted via the network to the packet handler.
Further features and advantages of the present invention will be apparent from the ensuing description with reference to the accompanying drawings to which, however, the scope of the invention is in no way limited.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a block diagram of one example of a conventional remote line concentrator in which a digital subscriber's line and an analog subscriber's line are accommodated;
Figs. 2A and 2~ show a formation of a digital subscriber's line and a format of D channel data pre-scribed by the CCITT;
Fig. 3 is a block diagram showing a principle of the present invention;
Fig. 4 is a block diagram of one embodiment of a remote line concentrator in which a digital subscriber's line and an analog subscriber's line are accommodated;
Fig. 5 is a block diagram of one embodiment of D channel handler shown in Fig. 4;
Fig. 6 is a diagram explaining a function of the D channel handler shown in Fig. 5; and Fig. 7 is a block diagram of one embodiment o~ a signal control device shown in Fig. 4.
DESCRIPTIO~ OF THE PREFERRED EMBODIMENT
A conventional remote line concentrator in which the digital subscriber's line and the analog subscriber's line are accommodated has, for example, a construction as shown in Fig. 1. In Fig. 1, la ~ ln are digital - ~1.26~
subscribers, 2a ~ 2n are analog subscribers t 3a ~ 3n are digital subscriber's lines, 4a ~ 4n are analog sub-scriber's lines, 5a ~ 5n are digital subscriber's line circuits (DLC), 6a ~ 6n are analog subscriber's line circuits (SLC), 7 is a D channel handler (DH), ~ is a scan/signal distributor (SCN/SD), 9 and 10 are multi-plexing/demultiplexing separators (MPX), 11 is a network (NW), 12 is a processor, and 13 is a packet handler (PH).
In this construction of the remote line, a concen-trator stage of a part of a master office (not shown inthe drawing) is set in a remote place, and a connection control is carried out in accordance with switching connection control information from the master office so that the network 11 processes the digital signals in the same way as in a digital switching system.
An interface between the digital subscriber and the switching system is, as shown in Fig. 2A, prescribed by the CCITT, and it is specified therein that the call control information which controls the low speed digital data and the call information, etc., via the digital subscrîber's line 3a ~ 3n from the digital subscriber la ~ ln is sent on the D channel (16 kb/s), and high speed data including voice information, etc., is sent on the B channel (6~ kb/s). In the digital subscriber's line circuit 5a ~ 5n, the D channel and the B channel -- are separated, and the da~a on the D channel is trans-ferred to the D channel handler 7.
The data on the B channel is multiplexed in the multiplexing/demultiplexing device 9, and is sent via the network 11 to the master office (not shown in the drawing). The data received via the master office is separated at the network 11 in the multiplexing/
demultiplexing device 9, and is sent via the digital subscriber's line circuits 5a ~ 5n to the predetermined subscriber la ~ ln.
In the D channel handler 7, the digital data and the call information compiled into packet form are _ 5 _ separated, and accordingly, the separated call control information is transferred to the processor 12, and the digital data is transferred to the packet handler 13.
The packet handler 13 outputs the digital data via the packet switchboard, etc. The processor 12 is used to control the call control information in the network 11. The D channel handler 7 is commonl~ used for all of the digital subscriber's line circuits 5a 5n, even in a construction having a plurality of multiplexingfdemultiplexing devices 9.
The information concerning an on-hook and off-hook, etc., by the subscriber 2a ~ 2n is transferred to the processor 12 by scanning and detecting signals in the analog subscriber's line circuits 6a ~ 6n by the scan/
signal distributor 8, and the processor 12 controls the network 11 accordingly. The analog voice signal is converted to a digital signal by the analog subscriber's circuits 6a ~ 6n, is multiplexed by the multiplexing/
demultiplexing device 10, and is sent via the network 11 to the master office.
The digital voice signal from the master office is separated via the network 11 in the multiplexing/
demultiplexing device 10, is converted to an analog voice signal in the analog subscriber's line circuits 6a ~ 6n, and is sent to the analog subscriber. In this - case, the scan/signal separator 8 is commonly used, even if a plurality of the multiplexing/demultiplexing devices 10 are used.
In the processor 12, the call control information from the analog subscriber is received via the scan/
signal separator 8 and the call control information from the digital subscriber is received via the D channel handler 7. Therefore, it has a drawback in that the construction becomes complex because the interfaces of the call control information are different in the analog subscriber and the digital subscriber.
Further, the D channel handler 7 and the scan/signal ~2601~4 separator 8 are centralized, so that the construction becomes comparatively large scale. Then, when the ratio between the digital subscriber and the analog subscriber changes, a drawback arises in that the D channel handler 7 or the scan/signal distributor 8 becomes uneconomical.
In the subscriber's line switching control system of the present invention, the call control information and the digital data in the D channel are transferred via the network. This will be explained with reference to Fig. 3. In Fig. 3, the digital subscriber's line 21 and the analog subscriber's line 22 are connected to the network 24 of the digital switchboard via the sub-scriber's line interfacer 23 including the subscriber's line circuits or the multiplexing/demultiplexing device, etc. The call control information from the subscriber is compiled into packet form in the subscriber's line interfacer 23, and the call control information in the packet form is transferred via the network 24 to the signal control device 25 r and thus the processor 27 controls the network 24 in accordance with the control information from the signal control device 25. Further, the digital data via the digital subscriber7s line 21 is transferred to the packet handler 26 directly connected to the network 2~, or to a packet handler provided in another office.
The call control information from the diyital subscriber ana the analog subscriber is compiled into packet form in the subscriber's line interfacer 23, and transferred via the network 24 to the signal control device 25, so that similar processes can be carried out for the digital subscriber's line 21 and the analog subscriber7s line 22. ~s the digital data in the form of packet data is also transferred via the network 24, if a packet handler 26 is set in another office, such as the master office, etc., the digital data can be trans-ferred thereto.
Figure 4 is a block diagram of the embodiment of the present invention, and shows the present invention when applied to the remote line concentrator as in the prior art shown in Fig. 1. In Fig. 4, 21a ~ 21n are digital subscribers, 22a ~ 22n are analog subscribers, 29a ~ 29n are digital subscriberls lines, 30a ~ 30n are analog subscriber's lines, 31a ~ 31n are digital sub scriber's line circuits tDLC), 32a ~ 32n are analog subscriber's line circuits (SLC), 32 is a D channel handler ~DH), 33 is a scan/signal distributor (SCN/SD), 34, 35 are multiplexing/demultiplexing separators (MPX), 24 is a network (NW), 27 is a processor which controls the network and other portions, 2~ is a packet handler (PH), and 25 is a signal control device (SIG).
The D channel handler 32 is provided for each multiplexing/ demultiplexing device 34, and the scan and signal distributor 33 is provided for each multiplexing/
demultiplexing device 35. The multiplexing/demulti-plexing devices 34, 35 each carry out the multiplexing and the demultiplexing for, for example, 6~ subscribers.
Therefore, when the number of digital subscribers 21 or analog subscribers 22 is more than 60, additional multiplexing and demultiplexing device 34, 35 are provided at every integral number of 60, and accordingly, a D channel handler 32 or the scan/signal distributor 33 is provided for each additional multiplexing/demulti-plexing device.
The D channel, which is transferred from the digital sllbscriber 21 via the digital subscriber's line 29 to the digital subscriber's line circuit 31 and is separated in the digital subscriber's line circuit 31, is transferred to the D channel handler 32. The call control information is separated in this D channel handler 32 and transferred from the multiplexing/demulti-plexing device 34 via a path ~ shown by the broken - 35 line in the network 24 to the signal control circuit 25, and the call control information is then transferred from the signal control device 23 to the processor 27, -` ~LX~ 4 so that control of the network 24 is carried out. For example, a path ~ in the network 24 is formed by the call control information of the call, and the digital data separated in the D channel handler 32 is transferred 5 from the multiplexing/demultiplexing device 34 via the path ~ shown by broken line in the network 24 to the packet handler 26~
The data of the B channel is sent from the digital subscriber's circuit 31 via the multiplexing/demulti-plexing device 34 and the network 24 to the master officeO The data of the B channel from the master office side is supplied via the network 24 to the multiplexing/demultiplexing device 34, where it is separated and synthesized with the data of the D channel in the digital subscriber's line circuit 31, and then transferred via the digital subscriber's line 29 to the digital subscriber 21. As a result, communication between the digital subscribers is established.
The analog subscriber's line circuit 32 is scanned in the scan/signal distributor 33, the call control information of the analog subscriber is detected, the detected call control information is compiled as the packet form and is multiplexed in the multiplexing/de-multiplexing device 35, and is then transferred via the path ~ shown by broken line to the signal control circuit 25. The control information is sent from this signal control circuit 25 to the processor 27 to control the network 2~, and then the line concentrating con-nection for the master office is carried out by the network 24. Subsequently, the voice information from the analog subscriber 22 is converted to a digital signal in the analog subscriber's line circuit 32 and is sent from the multiplexing/ demultiplexing device 35 via the network 24 to the master office. Conversely, the digital voice information from the master office is supplied via the network 24 to the multiplexing/demulti-plexing device 35 to be demultiplexed, convertea to an . g analog signal in the analog subscriber's line circuit 32 and transferred to the analog subscriber 22, and thus communication between the subscribers is established.
The signal control device 25 or the packet handler 26, etc., may be included at the side of the multi-plexing/demultiplexing device 34, 35 in the network 24, and the connection between the subscribers connected in the network 24 can be simply controlled by analyzing the dial information in the processor 27.
Next, the D channel handler 32 and the signal control device 25 will be described in detail. Before that explanation, however, referenc~ is made to the D channel data format shown in Fig. 2B. This format is prescribed in Q921 of the CCITT. In Fig. 2B, F denotes a flag which is fixed binary pattern of 01111110;
A denotes an address field;
C denotes a controlled field which contains a sequence number for error recovery;
N(S) denotes a transmitter send sequence number;
N(R~ denotes a transmitter receive sequence number; and, FCS denotes a frame check sequence generated by a polinominal X15 ~ X12 ~ X5 ~ 1 This is as prescribed in Q921 of the CCITT.
- Figure 5 is a block diagram of the D channel handler. In Fig. 5, 51 is a microprocessor unit (MPU), 52 is a memory (MEM), and 53a ~ 53n, 54, 55 are high level data link controllers (HDLC).
When the D channel handler receives the D-channel data from the subscriber's line, the D-channel data (16 k bit/s) is input to the high level data link controllers 53a ~ 53n. The hardware included in the high level data link controller 53a ~ 53n detects the flag F shown in Fig. 2B and carries out the delimitation of the message unit and checks by using the FCS in the format, and only residual A and C fields and the infor-~x~o~
mation are transferred to the memory 5?~
The microprocessor 51 reads the received data and carries out the following process.
a) In the A-field, there is an identifier of whether it is signalling information or user packet, and the microprocessor unit discriminates which kind it is by that identifier.
If it is signalling information, a further process on the sequence number included in the C-field is made by a D-channel protocol (LAPD. link access procedure D~. When it is a normal signal, it is accepted and the content of the information is sent to the signal control device 25 (SIG).
If it is a user packet, it is transferred to the packet handler 26 (PH).
b) The content of the information sent to the signal control device 25 is added by the processing of the microprocessor unit 51 of the A, C field based on the protocol transferred between the D-channel handler and the signal control device, and it is transferred to the high level data link controller 54. (Flag and FCS
are added in the controller 54 and sent to the signal control device 25.) c) With respect to the packet transferred to the packet handler 25~ only the A-field is converted and transferred to the controller 55. The flag and FCS is added to the A-field and is sent to the packet handler 26.
The proces~ing o~ the data received from the signal control device or the packet handler is carried out is the reverse of that shown above.
The above-mentionea function is graphically shown in Fig. 6.
In Fig. 6, when the data is received from the subscriber, the signalling information and the user packet are sepaxated in the blocks 61a ~ 61n, and are merged when the data is sent to the subscriber. In the ~2603L~L~
LAPD process 62, 63, the data received or sent by the subscriber is data link controlled based on the D-channel link access procedure (LAPD). In the data link con-trol 65, the error recovery process based on the data link control protocol between the signal control device and the D-channel handler is carried out. In practice, a process similar to the LAPD process is used~
Figure 7 is a diagram showing the signal control device. In Fig. 7, 71 is a microprocessor unit ~MPU), 72 is a memory (MEM), 73a ~ 73n are high level data link controllers (HDLC), and 74 is a channel interface controller (CHIC).
In Fig. 7, ~hen the data received from the D channel handler is processed, the data from the D channel handler is input to the controllers 73a ~ 73n, the process explained in the description of Fig. 5 is carried out, and the content of the processed information is transferred via the channel interface controller 74 to the processor 25. When the data is receive~ at the processor 25, a process that is, the reverse of that described above is carried out.
The above embodiment is described iIl the case when the present invention is applied to the line concen-trator, but the present invention can be applied also to a terminal office in which the subscriber's line is connected. Further, this embodiment shows the case when the packet handler 26 is directly connected in the network 24, but it is possible to set the packet handler in another office such as the master office, etc. That is~ there is no restriction of the position at which the packet handler 26 is set.
As mentioned above, in the present invention, the call control information of the subscriber is compiled in packet foxm in the subscriber line interfacer 23, and this call control information is transferred via the network 2q to the signal control circuit 25. The digital data via the digital subscriber's line 21 is 60~2~
transferred via the network 24 to the packet handler 26.
Therefore t both the call control information of the digital subscriber and the call control infoxmation o the analog subscriber, which are compiled in packet form, are transferred to the signal control circuit 25, and therefore, the same control can be carried out for the digital subscriber and for the analog subscriber from the processor 27.
Further, compared to the prior art, the number of cables for transferring the call control information is decreased, and therefore an economical construction can be obtained. Further, the position at which the packet handler 26 is set is not restricted, and when the present invention is applied to a remote line concen-trator device, etc., the packet data may be transferredto the master office via the network 24, and therefore the construction can be made more economical.
Further, the D channel handler 32 and the scan/
signal distributor 33 are provided for the multiplexing/
demultiplexing devices 34, 35, to attain a distributed control construction, and therefore, when the inclusion ratio for the digital subscriber and the analog sub-scriber is changed, a flexible response can be realized.
Claims (4)
1. A subscriber's line switching control system comprising:
a network of a digital switching system which accommodates via a subscriber's line interfacer one or both of a digital subscriber's line and an analog subscriber's line;
a packet handler which is connected directly to said network and a signal control device which is connected in said network or which is provided in another office; and a processor which controls said network according to control information from said signal control device, so that call control information is compiled into a packet form in said subscriber's line interfacer, said call control information is transformed in said packet form via said network to said signal control device, and digital data via said digital subscriber's line is transferred via said network to said packet handler.
a network of a digital switching system which accommodates via a subscriber's line interfacer one or both of a digital subscriber's line and an analog subscriber's line;
a packet handler which is connected directly to said network and a signal control device which is connected in said network or which is provided in another office; and a processor which controls said network according to control information from said signal control device, so that call control information is compiled into a packet form in said subscriber's line interfacer, said call control information is transformed in said packet form via said network to said signal control device, and digital data via said digital subscriber's line is transferred via said network to said packet handler.
2. A subscriber's line switching control system according to claim 1, wherein said subscriber's line interface comprises a plurality of digital subscriber's line circuits connected via digital subscriber's lines to digital subscribers, a first multiplexing/demulti-plexing separater connected to said digital subscriber's line circuits, a D channel handler provided corresponding to said first multiplexing/demultiplexing device, a plurality of analog subscriber's line circuits connected via analog subscriber's lines to analog subscribers, a second multiplexing/demultiplexing separator connected to said analog subscriber's line circuits, and a scan/
signal distributor provided corresponding to said second multiplexing/ demultiplexing device, said digital subscriber's line circuits separating said D channel from signals transmitted via said digital subscriber lines and said D channel being transferred to said D channel handler where said call control information is separated from said D channel, and said separated call control information being transferred via said first multiplexing/demultiplexing separator to said signal control device; and digital data separated in said D channel handler being trans-ferred via said first multiplexing/demultiplexing separator to said packet handler;
said scan/signal distributor scanning said analog distributor circuits, detecting said call control information of said analog subscribers, the detected call information being compiled into a packet form, multiplexed, and transferred to said signal control device.
signal distributor provided corresponding to said second multiplexing/ demultiplexing device, said digital subscriber's line circuits separating said D channel from signals transmitted via said digital subscriber lines and said D channel being transferred to said D channel handler where said call control information is separated from said D channel, and said separated call control information being transferred via said first multiplexing/demultiplexing separator to said signal control device; and digital data separated in said D channel handler being trans-ferred via said first multiplexing/demultiplexing separator to said packet handler;
said scan/signal distributor scanning said analog distributor circuits, detecting said call control information of said analog subscribers, the detected call information being compiled into a packet form, multiplexed, and transferred to said signal control device.
3. A subscriber's line switching control system according to claim 2, wherein said D channel handler comprises a first high level data link controller connected to said digital subscriber's line circuits, a second high level data link controller connected to said signal control device, a third high level data link controller connected to said packet handler, a micro-processor unit, and a memory;
wherein, when the D-channel data is received from said digital subscriber's line circuits, said data is stored in said first high level data link controller, said first high level data link controller transfers information included in said data to said memory, said microprocessor reads the data transferred to said memory; and said microprocessor transfers the content of said information to said signal control device if said information is signalling information, and transfers the content of said information to said packet handler, and when data is received from said signal control device or said packet handler, a reverse operation to that described above is carried out.
wherein, when the D-channel data is received from said digital subscriber's line circuits, said data is stored in said first high level data link controller, said first high level data link controller transfers information included in said data to said memory, said microprocessor reads the data transferred to said memory; and said microprocessor transfers the content of said information to said signal control device if said information is signalling information, and transfers the content of said information to said packet handler, and when data is received from said signal control device or said packet handler, a reverse operation to that described above is carried out.
4. A subscriber's line switching control system according to claim 1, wherein said signal control device comprises, a microprocessor unit, a memory, a high level data link controller connected to said D channel handler, and a channel interface controller connected to said processor, when data is received from said D channel handler, said data is stored in said high level data link controller, said high level data link controller transfers information included in said data to said memory, said microprocessor reads said information and transfers said information via said channel interface controller to said processor, and when data is received from said processor, a reverse operation to that des-cribed above is carried out.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60266072A JPH0666990B2 (en) | 1985-11-28 | 1985-11-28 | Subscriber line exchange control method |
| JP60-266072 | 1985-11-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1260124A true CA1260124A (en) | 1989-09-26 |
Family
ID=17425966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000523471A Expired CA1260124A (en) | 1985-11-28 | 1986-11-20 | Subscriber's line switching control system |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US4761779A (en) |
| JP (1) | JPH0666990B2 (en) |
| CA (1) | CA1260124A (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0714164B2 (en) * | 1987-02-19 | 1995-02-15 | 富士通株式会社 | Header driven packet switch |
| JPS63283256A (en) * | 1987-05-15 | 1988-11-21 | Nippon Telegr & Teleph Corp <Ntt> | Signal processing system |
| US4922484A (en) * | 1987-07-22 | 1990-05-01 | Nec Corporation | ISDN remote switching unit for accommodating analog and digital lines |
| JPS6444116A (en) * | 1987-08-12 | 1989-02-16 | Nec Corp | Matrix switch system |
| US4903263A (en) * | 1988-10-03 | 1990-02-20 | Network Access Corporation | Apparatus and method for providing existing telephone switching equipment with integrated services digital network capability |
| FR2646036B1 (en) * | 1989-04-13 | 1995-08-18 | Cit Alcatel | MULTI-SERVICE DIGITAL SATELLITE CENTER IN ASYNCHRONOUS SUBSCRIBER CONNECTION TIME TECHNOLOGY |
| JPH0388534A (en) * | 1989-08-31 | 1991-04-12 | Hitachi Ltd | Packet switching system |
| CA2025645C (en) * | 1989-09-19 | 1999-01-19 | Keiji Fukuda | Control channel terminating interface and its testing device for sending and receiving signal |
| CA1331215C (en) * | 1989-09-29 | 1994-08-02 | Andrew Lazlo Aczel | Resource-decoupled architecture for a telecommunications switching system |
| ATE143549T1 (en) * | 1991-05-08 | 1996-10-15 | Siemens Ag | CONTROL ARRANGEMENT FOR A BROADBAND SWITCHING SYSTEM |
| US5345443A (en) * | 1992-04-30 | 1994-09-06 | At&T Bell Laboratories | Network-based digital bandwidth-on-demand |
| WO1994005120A1 (en) * | 1992-08-25 | 1994-03-03 | Siemens Aktiengesellschaft | Switching control system for controlling physical connection structures in a communications system |
| US5579300A (en) * | 1993-06-14 | 1996-11-26 | Hyundai Electronics Industries Co., Ltd. | Private automatic branch exchange for integrated services digital network |
| JPH07193626A (en) * | 1993-12-27 | 1995-07-28 | Nec Corp | Voice reply device compatible with isdn line and analog line |
| JP2636731B2 (en) * | 1994-05-23 | 1997-07-30 | 日本電気株式会社 | Private branch exchange system data transfer method |
| SE515417C2 (en) * | 1996-03-29 | 2001-07-30 | Ericsson Telefon Ab L M | Device and method for establishing communication |
| JPH09271085A (en) * | 1996-04-03 | 1997-10-14 | Fujitsu Ltd | Data link processor and subscriber's terminal equipment |
| US6101216A (en) * | 1997-10-03 | 2000-08-08 | Rockwell International Corporation | Splitterless digital subscriber line communication system |
| US6445733B1 (en) | 1997-10-03 | 2002-09-03 | Conexant Systems, Inc. | Method of and apparatus for performing line characterization in a non-idle mode in a subscriber line communication system |
| US6442169B1 (en) | 1998-11-20 | 2002-08-27 | Level 3 Communications, Inc. | System and method for bypassing data from egress facilities |
| US6614781B1 (en) | 1998-11-20 | 2003-09-02 | Level 3 Communications, Inc. | Voice over data telecommunications network architecture |
| US7324635B2 (en) | 2000-05-04 | 2008-01-29 | Telemaze Llc | Branch calling and caller ID based call routing telephone features |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4627047A (en) * | 1982-01-07 | 1986-12-02 | Rockwell International Corp. | Integrated voice and data telecommunication switching system |
| JPH0628361B2 (en) * | 1984-11-27 | 1994-04-13 | 国際電信電話株式会社 | Packet exchange method |
| US4644527A (en) * | 1985-04-29 | 1987-02-17 | At&T Bell Laboratories | Interface unit for transferring voice and data signals |
-
1985
- 1985-11-28 JP JP60266072A patent/JPH0666990B2/en not_active Expired - Lifetime
-
1986
- 1986-11-20 CA CA000523471A patent/CA1260124A/en not_active Expired
- 1986-11-20 US US06/932,621 patent/US4761779A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62128295A (en) | 1987-06-10 |
| US4761779A (en) | 1988-08-02 |
| JPH0666990B2 (en) | 1994-08-24 |
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