Patent Application
20050025128
This invention is generally directed to telecommunication services and is more specifically directed to private branch exchanges (PBXs) and services made available to users by a PBX.
Commonly known circuit private branch exchanges are normally located remote from a supporting telecommunications switch and are normally installed near the customers to be served by the PBX. For example, employees of a business occupying several floors of a large office building would be served by a PBX located in the office building. Such a PBX would be typically owned by the business, i.e. the customers served, and could be connected to a supporting class 5 telecommunication switch by an ISDN primary rate interface (PRI) communication line. A circuit PBX provides a substantial number of features to its customers such as the ability of a customer to utilize abbreviated digit dialing when calling another customer also supported by the PBX.
Another type of PBX is an Internet protocol (IP) PBX. The IP PBX is similar to the circuit PBX in that is normally purchased by the business that it supports and is located at the location of the business. The IP PBX typically interfaces to a class 5 telecommunication switch by a PRI or Session Initiation Protocol (SIP) communication line. It is similar to the circuit PBX in that it provides a substantial number of features to its customers. The IP PBX provides an interface for and supports the connection of IP telephone sets that carry customer communications by IP packets.
Although the IP PBX provides a variety of call related features to the supported customers, some features that would be available from a telecommunication switch's Centrex facility are not available to customers of an IP PBX. For example, a number of electronic directory service (EDS) features, such as calling name display, directory query display and auto call, which would be available to a subscriber of Centrex services, are not available to customers of an IP PBX. One reason why such services are not available to customers of an IP PBX is that an interface is not available to the applications processor (AP) associated with the supporting class 5 switch. The applications processor is coupled to and facilitates communications with a directory database that contains attributes associated with each subscriber such as the person's name, telephone number, location, organization, etc. Since the IP PBX is an external peripheral from the perspective of the supporting class 5 switch, communications and messages between the switch's applications processor and the IP PBX are not supported. Therefore, a need exists to provide a full range of call features for IP telephone set subscribers.
It is an object of the present invention to provide a solution for this need.
In accordance with an embodiment of the present invention, a method is implemented by a supporting switch to provide IP telephone set subscribers with call features such as found in Centrex systems. An IP peripheral unit, IPPU, of the switch receives a first IP packet from an IP subscriber containing a request for a first call feature. The IPPU converts the first IP packet into a second message transmitted to a packet line trunk unit (PLTU) of a switch module over a PCTFI interface, where the second message contains the request for the first call feature. First information contained in a directory database is accessed by an applications processor based on the request for the first call feature contained in the second message. The applications processor retrieves at least a portion of said first information. The retrieved portion of the first information is utilized to implement the requested call feature by the IP telephone set subscriber.
Telecommunication switch 10, which may comprise a class 5 telecommunication switch such as the 5ESS® switch available from Lucent Technologies Inc. that includes an administrative module (AM) 22, a communications module (CM) 24, and a plurality of switch modules (SM) represented by switch modules 26 and 28. The administrative module 22 is responsible for the overall call routing and control functions, as well as operations, administration and maintenance functions. The communications module 24 is responsible for interconnecting information contained in time slots representing telephone calls between the switch modules. The switch modules 26 and 28 provide a termination for subscriber and trunk lines and translate the information contained on these lines into information carried by respective time slots. An optical interface unit 30 that supports IP protocol communications (OIU-IP) provides an interface between switch module 28 and the optical trunk line 16 coupled to IP PBX 14. An applications processor 32 is coupled to the switch modules and to a directory database 34 that contains subscriber information and attributes relating to each subscriber such as a person's name associated with a directory telephone number, location, organization, position within the organization, etc. However, because the IP PBX 14 is an external peripheral of switch 10, communications and messages between the IP PBX 14 and the applications processor 32 are not supported. Hence, an IP telephone set subscriber 20 of IP PBX 14 can be provided with services and call features such as through EBS peripheral 18, but the IP telephone set subscriber cannot be offered call features that require support of the applications processor 32.
In
Telecommunication switch 50 is preferably based on a class 5 switch such as a 5ESS® switch available from Lucent Technologies Inc. It includes an administrative module 70, a communications module 72, and exemplary switch modules 74 and 76. Switch module 76 includes a commercially available packet line trunk unit (PLTU) 78 that supports communications via peripheral control & timing facility interface 79. An applications processor 80 is coupled to the switch modules and to a directory database 82. An Internet protocol peripheral unit (IPPU) 84 includes network interface card (NIC) 86 and a peripheral control and timing (PCT) interface card (PIC) 88. The IPPU 84 can comprise an iMerge Centrex Feature Gateway available from Lucent Technologies Inc. modified by the addition of PIC 88 that will be described below.
In
A YES determination by step 104 indicates that information (user communications or command signaling) is required to be transmitted to the SM. In step 110 PIC 88 generates a PCT facilities interface (PCTFI) compatible message based on the required services, payload, and address associated with the incoming packet. In step 112 the PCTFI compatible message is transmitted from PIC 88 to PLTU 78 of the SM 76. The common interface and protocol between the PLTU and the PIC is referred to as PCTFI. Processing concludes at END step 114.
A YES determination by step 124 results in the payload and address information being transferred from the IPPU 84 to the NIC 86 in step 130. In step 132 the NIC 86 generates an IP packet based on the payload and address information, and transmits it to the IP network 54. The process concludes at END step 134. Thus, outgoing messages may contain command and control information for IPPU 84 or communications to be forwarded to a subscriber.
In order to better appreciate the significance of the feature implemented by the signaling diagram, it will be helpful to understand the advantages provided over current IP PBX systems. In a current IP PBX system, assuming users A and B belong to the same PBX group and that user A calls B by dialing B's extension telephone number, user B would not have displayed on his telephone set user A's name, calling number (user A's number) or other information about user A. Changing the scenario, if users A and B belonged to a Centrex calling group, then the telephone set of the called party B would display the name and directory number of the calling party A. As will be explained with regard to
The calling party 200 (IP telephone set 58) and the called party (IP telephone set 62) both belong to the same business group. User A generates an off hook signal 208 that is transmitted to switch 202 (switch 50) by an IP packet transmitted through corporate LAN 56, IP network 54 to the NIC 86 of IPPU 84. This information is translated into an appropriate PCTFI message transmitted from PIC 88 to PLTU 78 of SM 76. Upon determining that call capacity exists a handle the newly requested incoming call, switch 202 generates a dial tone signal 210 that flows through PLTU 78, PIC 88, NIC 86, IP network 54, and corporate LAN 56 to IP telephone set 58. This results in dial tone being provided user A. User A enters the directory number of user B as indicated by signal 212. Since both users are members of the same call group, the dialed directory number may consist of only the extension number associated with user B. The dialed digits are transmitted to switch 202 as a message(s). Upon receiving the extension number of user B, switch 202 recognizes that the requested call is to another user of the same call group and user B is equipped with the calling name display feature, the switch 202 transmits a signal 214 to applications processor 204 requesting name information associated with the calling party based on the calling party's directory number that was transmitted to the switch as part of the call origination. The applications processor 204 locates a record stored in the directory database 82 corresponding to the calling party's directory number, and retrieves the stored name of user A. Applications processor 204 transmits the retrieved name information of user A by signal 216 to switch 202.
Switch 202 generates a signal 218 transmitted to user A causing the IP telephone set 58 to generate an audible ringing tone to the calling party, user A. The switch 202 also generates a signal 220 transmitted to user B causing the IP telephone set 62 to initiate ringing. The switch 202 further sends a signal 222 to the user B's IP telephone set that carries the directory number and name of the calling party, user A. Upon answering the incoming call by user B, an off hook signal 224 is transmitted from the IP telephone set 62 to the switch 202. Upon receipt of the off hook signal, switch 202 establishes a two-way bearer communication path, talking path 226, between users A and B to facilitate user communications.
Switch 202 transmits a signal 240 to user A indicating that the user can proceed with the desired name query; this indication will typically be shown on display of the user's IP telephone set. User A then proceeds to enter a series of digits representing the alphabetical spelling of the desired name as indicated at signal 242 that is transmitted to switch 202. On receipt of the query, switch 202 transmits a signal 244 to user A indicating that the requested query is being processed; typically this information will be shown on the display of user A. The switch 202 transmits a query request containing the received name from user A as signal 246 to applications processor 204. The applications processor 204 provides a search of the directory database 82 to identify a record corresponding with the input name. Upon locating a corresponding record, applications processor 204 transmits a signal 248 to switch 202 containing the relevant information associated with the record that may include the directory number, name, location, position in the organization, etc. The switch 202 relays the received relevant information as signal 250 to user A and the information is displayed on user A's IP telephone set 58. Thus, user A as an IP PBX user is provided with a capability that supports directory queries just as would have been made available to a Centrex subscriber.
Another advantage of the present invention is that operations, administration, maintenance and provisioning (OAM&P) is integrated for the switch and the IP interface, the IPPU of the embodiment. As shown in
Various changes and additions can be made to the illustrative embodiments by those skilled in the art. The present invention is not limited to the specific embodiments shown. The scope of the present invention is defined by the claims that follow.
