Method of processing special service telephone calls

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METHOD OF PROCESSING SPECIAL SERVICE
TELEPHONE CALLS

TECHNICAL FIELD 5

This invention relates generally to communication call processing and to a method for providing customized call services to subscribers by means of the CCIS (Common Channel Interoffice Signaling) system. In particular, the invention pertains to a method of verifying the entitlement of calls to customized call treatment in a telephone system in which not all offices are equipped with CCIS capability.

BACKGROUND OF THE INVENTION 15

Until recently, telephone signaling systems have been provided almost exclusively on a per trunk in-band basis. That is, supervisory and called address signals have been transmitted over voice facilities in the pro- 2Q cess of establishing call connections. The CCIS system was recently introduced into service for the purpose of improving the signaling capacity and flexibility for the establishment of call connections from the voice facilities of the telephone network. 25

The CCIS system is a data communications network interconnecting telephone offices. Telephone offices that interface with the CCIS system are said to have CCIS capability. These offices have access to data links which are routed directly or indirectly through signal 30 transfer points (STPs), to other offices having CCIS capability. The data links may also provide access from telephone offices to centralized data bases at which may be stored subscriber data for providing such services as enhanced Inward-Wide-Area-Telephone-Service (IN- 35 WATS), now called "800 service."

The CCIS system now in operation employs a signaling arrangement in which all data messages are depen- dent on the existence of a particular voice facility. That is, each signaling data message now transmitted in the 40 CCIS system contains an identification of a voice trunk selected for a call with which the data message is associated. The voice trunk identification provides the address of the destination (switching office) of the data message. Data messages are transmitted from destina- 45 tion to destination as a call is progressively established. In the near future a new form of signaling, referred to as direct signaling, will be introduced. Direct signaling messages may be sent directly to a final destination and do not have to be associated with a telephone call or 50 with a voice trunk. These messages might contain, for example, network management information.

Direct signaling will allow the introduction of a host of new calling services to telephone customers. Many of these new services may be described as customized and 55 may depend upon identifying the calling entity (party or station) or some other call identifying characteristic which entitles the call to some type of treatment different from ordinary calls. U.S. patent application Ser. No. 113,384, filed by D. Sheinbein on Jan. 18, 1980, de- 60 scribes in detail how some of these customized calls might be provided. Illustrative examples of the types of customized services that are planned include selective call acceptance, selective call waiting, selective automatic callback, priority ringing, etc. In selective call 65 acceptance, for example, a subscriber prespecifies individuals or stations from which calls may be accepted. Calls from other individuals or stations are denied. Simi

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larly, the other selective services mentioned above are provided on the basis of prespecified calling entities.

Up to the present time, it has been considered impossible to process these types of customized calls without end-to-end CCIS signaling. That is, it has been believed that all offices involved in the routing of such a call must have CCIS capability. The Sheinbein disclosure, for example, assumes that all offices in a call connection have access to the CCIS system. The reason for this is the need of identification at the terminating office to verify the entitlement of the call to the customized service. For example, in order to apply priority ringing to a subscriber's station who leases this service, a terminating office must verify that an incoming call is from an entity the subscriber has authorized for the priority ringing. In general, the method that has been contemplated for providing this information to the terminating office is to transmit CCIS data messages between each of the offices involved in the call. The messages would identify the calling entity and the interoffice trunk on which the call is being routed. In this manner, the terminating office would eventually receive a CCIS data message identifying the trunk on which a call is arriving and the calling entity associated therewith. The terminating office would then communicate with a data processing facility, for example, to determine if the called party subscribes to some type of customized service and if so, if the calling entity is authorized for the service.

In the event that a toll office, for example, used in establishing a call does not have CCIS capability, there is no way in the above-described method for that office to notify the succeeding office of what outgoing trunk is selected for the call. Even if the succeeding office has CCIS capability and is given a call identification by a data message from a prior office, there is no way for the succeeding office to associate the identity with a particular call arriving on a voice trunk. The result is that there is no way to identify the calling entity on a call arriving at the terminating office and, therefore, no way for the terminating office to verify the entitlement of the call to custom calling service.

It is expected that CCIS custom calling services will begin to be offered to the public in the near future. Under current thinking, however, only limited service can be offered until CCIS capability is universally available in the telephone network. This universal capability probably will not be achieved for many years. The lack of universal CCIS capability is therefore a serious detriment to the rapid introduction and acceptance of many new services.

SUMMARY OF THE INVENTION

The foregoing problem is solved, and a technical advance is achieved by a method of processing customized telephone calls in a system comprising a plurality of telephone offices, voice facilities, and a data communications network interconnecting prescribed ones of the offices. A fictitious number is assigned to a call in response to a determination that the call is entitled to customized service. The fictitious number identifies the call as so entitled. The identity of the called entity is stored in association with the fictitious number. Thereafter, the call is completed to a terminating office using the fictitious number. When the terminating office receives a call directed to a fictitious number, it obtains the identity of the called entity using the fictitious number and completes the call to the called entity with customized treatment.

In a preferred embodiment, in response to a telephone call at a first one of the offices, data identifying the calling and called entities are transmitted via the data communications network directly to the terminating office. The terminating office verifies from the identifying data the entitlement of the call to customized service. If the call is so entitled, the terminating office assigns a fictitious telephone number to the call and transmits the fictitious number to the first office. The terminating office also stores the fictitious number in association with the called entity identifying data received from the first office and with data identifying the customized service to which the called entity subscribes. The first office completes the call using the fictitious telephone number. When the call to the fictitious telephone number arrives at the terminating office, the terminating office determines from the stored data whether or not the fictitious number is assigned to a call. If so, the terminating office obtains the true number of the called entity from storage and completes the call to that entity, providing whatever customized services are authorized. The fictitious number is then made available for assignment to another call.

The foregoing method identifies a call arriving at a terminating office as one which is entitled to customized service. The method achieves this without requiring that every office involved in the completion of the call be equipped with facilities for interconnecting with the CCIS network. All that is required is that the terminating office have CCIS capability and, if an interoffice call is involved, that the calling party have access to an office with CCIS capability which can determine the calling line number. The latter office is called an action control point (ACP) and may be the calling party's originating office, or if the originating office does not have CCIS capability, the ACP may be a toll office (equipped with CAMA trunks) or a traffic service position system (TSPS). The use of a TSPS as an ACP is particularly advantageous because it is accessible to virtually every telephone station in the country at the current time. Because of this universal accessibility, it is planned to rapidly provide all TSPSs with CCIS capability.

In the preferred embodiment, the fictitious numbers assigned to calls by a terminating office are spare line numbers in the office. An adequate plurality of the spare numbers are placed in a pool from which they are assigned to calls on an individual basis as needed. The ideal size of the pool of numbers for any given office is not known, as it will depend on the number of subscribers and the number of calls they receive. The size, however, is not expected to be large because the assignment of a fictitious number to a call lasts only for the time required to complete the call to the terminating office. At that time the temporarily assigned number is returned to the pool for reuse on a subsequent call.

A time audit of all numbers from the pool is performed in order to insure that the pool is not depleted by calls which are abandoned or which do not complete due to system malfunctions. When a number is assigned from the pool, the time of assignment is entered in storage with the number. Periodically, the time of assignment of all assigned pool numbers is compared to the current time; if a prescribed interval is exceeded for any given number, it is presumed that the call associated with the number has been abandoned or will not otherwise complete. In this case, the number is returned to the pool.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from a reading of the following detailed description in conjunction 5 with the drawings in which:

FIG. 1 shows, in block diagram form, a configuration of telephone switching offices, CCIS, and signal transfer facilities illustratively for serving customized types of calls in the United States; 10 FIGS. 2 through 6 show illustrative flow diagrams of a program at a terminating office for administering the assignment of fictitious numbers to calls.

FIG. 7 shows an illustrative Directory Number Translation Table (DNTT) for one subscriber at a ter15 minating office and among other items contains an address pointer to an illustrative call screening table (CST) associated with the station number of a subscriber to certain customized types of services. The CST table contains a list of station numbers of autho20 rized calling stations and the services to which these stations are authorized when calling the subscriber; and

FIG. 8 shows an illustrative variable memory table constituting the pool of fictitious numbers. Each table entry associated with a fictitious number has memory 25 slots for storing a called station number to which a pool number is assigned, a time of assignment, and an identification of the special services to which the called station subscribes.

With reference to FIG. 1, the method is described by assuming that a calling party A at station 10, having an area code and directory number of 415-445-3030, places a tool call to a party B at station 11. Station 11 is as

35 sumed to have an area code and directory number of 201-526-6789. It is assumed that the party B at station 11 is served by a local office 14 which has CCIS capability and that party B subscribes to selective call waiting and priority ringing service. It is further assumed that B has

40 prespecified that calls from station 10 are entitled to priority ringing.

It is also assumed that calling and called entities are identified by respective station numbers. It is possible, however, that the entities be identified by unique per

45 sonal numbers that are associated with the parties rather than with the stations. For example, in a new proposed service referred to as person locator service, telephone calls are placed to called parties by dialing personal numbers uniquely assigned to the called parties. The

50 calls are automatically routed to stations at which the called parties are located, or in lieu of call completion, announcements indicating reasons for the unavailability of called parties may be given to calling parties. Person locator service is described in detail in U.S. patent appli

55 cation Ser. No. 113,383, filed on Jan. 18,1980 by Jordan et al.

Station 10 is served by local office 12, which, it is assumed, does not have access to the CCIS system. In order to place a customized call from station 10, the call

60 must be routed through an action control point (ACP) which, it is recalled, is an office having access to the CCIS system. By way of example, TSPS office 13 is assumed to be the ACP in this example serving local office 12. The structure and operations of a TSPS office

65 are described in detail in U.S. Pat. Nos. 3,484,560, which issued to Jaeger et al on Dec. 16, 1979; 4,031,324, which issued to Dudonis on June 21, 1977, and 4,054,756, which issued to Cornelia et al on Oct. 18,