AU596915B2 - Call service initialization arrangement - Google Patents

Description

~~41~ )1 1: ID* I i 596915 S F Ref: 73653 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATIO

(ORIGINAL)

FOR OFFICE USE:

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Class It.. C Clas Class Int Class Complete Specification Lodged: Accepted: Published: Priority: .Related Art: o o Ji .Name and Address S° of Applicant: o o o s o 9 94 9 0 0 American Telephone and Telegraph Company 550 Madison Avenue New York New York 10022 UNITED STATES OF AMERICA Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Address S4 9 e 4 9 94 9 It 9 61I for Service: Complete Specification for the invention entitled: Call Service Initialization Arrangement The following statement is a S' est method of performing it full description of known to me/us this invention, including the 5845/3

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C~iLE SERVICE P'h'TYIAZATlON 0409 00 996 44 99 08 0 4 96 9 4 0 49 0 09 4 4 9 f .9 4.009w 9 I 944 6 4 94 Background and Problem Multiple terminals are connectable to a single digital subscriber line with an Integrated Services Digital Network (ISDN multipoint interface, defined in Recommendation 1.430 of the International Telegraph and Telephone Consultative Committee (CCITT). The multipoint interface allows a customer to add terminals without providing additional wiring to the customer premises. In the past, switching systems stored data defiing the call services for a terminal based on an equipment number associated with the line connecting the terminal to the switching system. Per-line service definition is ineffective, however, in a multipoint arrangement because it requires all terminals on a given digital subscriber line to have identical services. A customer, however, may need services to be defined individually for the terminals, requiring for example, differing feature button definitions for terminals on the same digital subscriber line.

One approach to the provision of individually defined services for terminals on a multipoint interface is to assign fixed terminal endpoint identifiers and store service data.in the switching system based on these terminal endpoint identifiers. Requiring assignment of fixed terminal endpoint identifiers at subscription time, however, increases the administrative overhead for adding new terminals or moving existing terminals to new locations. In such an arrangement, moving a terminal between digital subscriber lines requires a service order to update the data stored in the switching system. Thus, before adding or moving terminals, a customer submits a service order request and then waits, possibly several days, until the request is processed and the data are updated. Furthermore, since unique terminal endpoint identifiers are required for each terminal, adding 25 terminals, even terminals configured with the same services as another of the customer's terminals, requires a service order.

Moreover, in an arrangement having subscribed-to terminal endpoint identifiers, the switching system is unable to selectively address terminals in a message broadcast to all terminals on a digital subscriber line. CCITT Recommendation Q.931 requires broadcasting of certain messages such as messages offering incoming calls. If a customer requires a terminal to audibly alert for incoming calls to a pa-ticular directory number while another Scrinal on the same digital subscriber line silently alerts for calls to that directory n.umber, 2' 2 conflicting call setup messages are required. The switching system needs a mechanism to address each message to the appropriate terminals while still broadcasting the messages to all terminals on the digital subscriber line. When broadcasting on a digital subscriber line, the switching system must use a global terminal endpoint identifier rather than the individual terminal endpoint identifiers of each terminal. Thus, even when the service information specifies conflicting terminating treatment for different terminals, the switching system is unable to address messages to the appropriate terminals.

In view of the foregoing, a recognized problem in the art is the difficulty of providing conflicting call services for terminals in a multipoint configuration and allowing broadcast messages to 9* contain address information specifying particular terminals based on oI 15 the services enabled for each terminal while limiting the *911 administrative overhead for' adding and moving terminals.

According to one aspect of this invention there is provided a call service initialization method as claimed in claim 1.

According to another aspect of this invention there is provided a call service initialization method as claimed in claim 14.

According to a further aspect of this invention there is -provided a switching system as claimed in claim An exemplary embodiment of the invention includes a switching system that stores multiple service profiles each defining features subscribed to by a user without requiring assignment of terminal endpoint identifiers at subscription time, and the services defined by a service profile are enabled for a terminal in a multipoint configuration in response to transmission by the terminal of both a wow 30 first identifier defining the terminal and a second identifier defining a particular service profile for that terminal.

Advantageously, the first identifier is assignable by the switching system while the second identifier may be fixed for a given terminal and associated service profile. In this arrangement, terminals are moved between digital subscriber lines, without requiring a service J iNi L N Kr 2a order, simply by repeating the initialization process at the new location. New terminals with services defined by existing service profiles are added, without requiring a service order, simply by the terminal invoking initialization and sending the identifier for the existing profile. The switching system thereafter includes an identifier for a service profile within messages broadcast on the digital subscriber line. By including the identifier for a service profile within a broadcast message, the switching system selectively addresses terminals based on services enabled for the terminals while still fulfilling the requirement of broadcasting the message to all terminals.

*0 0 0 0 a 0 400 0000 0 9 0 00 0000 0s 0 ii i ii 4> r -3- An initialization method in accordance with the invention is used for a switch that is connectable to multiple terminals via a single line. The switch stores a number of service profiles each defining a set of call services. In accordance with the method, the switch receives on the line a first identifier defining one of the terminals and a second identifier defining one of the service profiles. The switch responds to receipt of the first and second identifiers by enabling for the defined terminal the set of call services of the defined service profile.

In an illustrative method of the invention, the switch also responds to receipt of the second identifier by determining third and fourth identifiers for use by the switch in addressing the terminal. The third identifier distinguishes the defined service profile from any other service profiles defining sets of call services enabled for only the multiple terminals on the single line. The fourth identifier distinguishes the defined terminal from any other terminals on the single line for which the set of call services of the defined service profile is enabled. The switch transmits the third and fourth identifiers to the terminal and thereafter addresses the terminal using the third and fourth identifiers.

To elaborate further, each terminal stores a service profile identifier defining one of the service profiles. To effect an initialization, a given terminal 20 generates a random number and includes the generated random number in a first message transmitted to the switch. The switch responds to the first message by determining a terminal endpoint identifier that is not assigned to any of the multiple terminals on the line. The switch assigns the determined terminal endpoint identifier to the given terminal. The switch then broadcasts a second message on the line including the random number received in the first message and the assigned terminal endpoint identifier. The given terminal responds to the second message by determining whether the random number received in the second message is the same as the random number it transmitted in the first message. Upon determiningthat the received random number is the same as the random number it transmitted, the given terminal stores the assigned terminal endpoint identifier and transmits a third message to the switch including the stored terminal endpoint identifier and the service profile identifier stored by the terminal.

The switch responds to the third message by determining the service profile defined by the service profile identifier included in the third message. The switch then enables a set of call services for the given terminal that is defined by the r t '2 4 determined service profile.

The invention will now be described with reference to the accompanying drawings in which: FIG. 1 is a diagram of an ISDN switch serving a plurality of ISDN terminals; FIG. 2 is a memory map for memory facilities in a control portion of the switch of FIG. 1; FIG. 3 is a memory map for memory facilities in a terminal of FIG. 1;

FIG.

a terminal terminal;

FIG.

a terminal 15 switch; 4 is a message sequence diagram for the initialization of in FIG. 1 where the initialization is initiated by the 5 is a message sequence diagram for the initialization of in FIG. 1 where the initialization is initiated by the 00 4 0 0 04 0000 0 r 0000 0r 04 5 *r 4 0 45 04

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FIG. 6 and FIG. 7 are message sequence diagrams for two call setup examples illustrating the use of addressing parameters established during initialization of a terminal of FIG. 1.

FIG. 8 is a state diagram for a terminal of FIG. 1; and 20 FIG. 9 is a state diagram for the switch of FIG. 1.

The present invention is described in the context of an integrated services digital network (ISDN) switch 1000 (FIG. An integrated services digital network is a network evolved from the telephony integrated digital network that provides end-to-end 25 digital connectivity to support a wide range of services, including voice and non-voice services, to which users have access by a limited set of standard customer interfaces. One example of ISDN switch 1000 is the integrated packet switching and circuit switching system disclosed in U.S. Patent 4,592,048 Beckner et al. Switch 1000 includes a switching network 1010, which represents, in the above-referenced exemplary integrated packet switching and circuit switching system, a plurality of time-slot interchange units and a time-multiplexed switch to provide circuit-switched connections, and a plurality of packet switching units (interconnected via the time-slot interchange units and time-multiplexed switch) to provide o t r O I ill 2 i ii.

4a packet-switched connections. Switch 1000 further includes control arrangement 1020 that represents the control portion of the above-referenced exemplary switching system, including a central control and a plurality of control units that communicate via predetermined channels of the time-multiplexed switch and a control distribution unit.

i 2 LI Each of three digital subscriber lines 31, 41, and 51 connected to switch 1000 provides 144 kb/s of user accessible bandwidth: 64 kb/s for each of two B channels and 16 kb/s for a D channel. While all terminals connected to each digital subscriber line receive a 144 kb/s bandwidth, each terminal does not always require the entire bandwidth. To increase bandwidth usage and decrease outside-plant wiring costs, the CCITT Recommendation 1.430 allows connection of multiple terminals to a single digital subscriber line in a point-to-multipoint configuration, using for example a passive bus arrangement.

The process used by switch 1000 to relate each terminal in a pointto-multipoint configuration with subscribed service information stored in memory 3000 of switch 1000 is defined below. First, an example is presented to illustrate how switch 1000 initializes the relationship between a terminal and subscribed service information. Next, several examples are presented to show how switch 1000 uses addressing parameters assigned during the initialization procedure to address individual terminals as well as related groups of terminals. Uses for this addressing method in call processing are also shown. Finally, a more detailed definition of the initialization procedure is given.

The following example illustrates the initialization procedure. In this l example, user A has three terminals 2310, 2320, and 2330. All of user A's terminals 2310, 2320, and 2330 are connected to switch 1000 via digital subscriber line 31. User B has two terminals 2340 and 2410. Terminal 2340 is connected to switch 1000 via digital subscriber line 31 and terminal 2410 is connected to switch 1000 via digital subscriber line 41.

CCITT Recommendation 1.441/Q.921 defines the link layer (layer 2) protocol implemented by switch 1000. The layer 2 protocol defines an address parameter, the terminal endpoint identifier (TEI), to identify each terminal on a given digital subscriber line. Each terminal 2310, 2320, 2330, 2340, and 2410 includes a memory to store the terminal endpoint identifier and other addressing parameters assigned to the terminal. For example, terminal 2310 includes memory 7310. A single physical device using multiple terminal endpoint identifiers for signaling is treated as multiple terminals. A terminal endpoint identifier, which can assume values from 0 to 127, is included in the address field of all layer 2 frames. Switch 1000 uses a terminal endpoint identifier with a value of 127, referred to as the global terminal endpoint identifier, to broadcast a single message to all terminals on a given digital subscriber line. When switch 1000

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-6transmits a message using the terminal endpoint identifier for a specific terminal, this is referred to as transmitting on a point-to-point link. When switch 1000 transmits a message using the terminal endpoint identifier of 127, this is referred to as transmitting a message on the broadcast link or simply as broadcasting.

A terminal endpoint identifier is either assigned automatically by switch 1000 or fixed, that is entered into a terminal by a user or a manufacturer.

Terminals 2310, 2320, 2330, 2340, and 2410 have automatically-assigned terminal endpoint identifiers. To request assignment of a terminal endpoint identifier, terminal 2310 generates a random number and includes the random number in a message that terminal 2310 transmits to switch 1000 on the broadcast link for digital subscriber line 31. This message and other messages referred to herein are transmitted on the D-Channel. When switch 1000 receives the message including the random number, switch 1000 reads a block 500 (FIG. 2) of memory 3000 to determine a terminal endpoint identifier that is not assigned to any of the other terminals 2320, 2330, and 2340 on digital subscriber line 31. Block 500 includes S linked lists of terminal endpoint identifier data blocks for each digital subscriber line. Switch 1000 searches the data blocks in block 500 to determine an o o unassigned terminal endpoint identifier for digital subscriber line 31. There is no 0 predetermined relationship between the terminal and the terminal endpoint 20 identifier assigned by the switch so switch 1000 chooses any identifier that is unassigned. Switch 1000 determines, for example, that the value of 65 is unassigned. In block 500, switch 1000 creates a data block 530 corresponding to 0 the terminal endpoint identifier of 65 on digital subscriber line 31. Switch 1000 o 0 transmits a message, containing the determined terminal endpoint identifier value of 65, on digital subscriber line 31 using the broadcast terminal endpoint 000:o identifier, 127. In this message, switch 1000 includes the random number received in the message from terminal 2310. On receipt of the message from switch 1000, terminal 2310 first compares the random number in the received message with the random number that terminal 2310 inserted in the request ,00 o30 message. In the present example, the random numbers are the same, indicating that the message is not a coincidental response to a request from another terminal on digital subscriber line 31. Terminal 2310 stores the assigned terminal endpoint identifier value of 65 in a block 900 of memory 7310.

r -7- This terminal endpoint identifier assignment exists only as long as the layer 2 link between terminal 2310 and switch 1000 remains established. For example, an automatically-assigned terminal endpoint identifier is removed when a terminal is disconnected. When terminal endpoint identifier removal occurs, terminal 2310 must repeat the above assignment procedure when it requires a terminal endpoint identifier. The terminal endpoint identifier assigned when the procedure is repeated is not necessarily the terminal endpoint identifier that was i' -tiously assigned.

Service profiles stored in a block 100 (FIG. 2) of memory 3000 describe the directory numbers and services to which a user has subscribed.

Service profile SP1 (FIG. 2) defines the directory numbers and the services subscribed to by user A for terminals 2310 and 2320. Service profile SP2 defines services subscribed to by user A for terminal 2330. Service profile SP3 defines services subscribed to by user B for terminals 2340 and 2410. Service profiles may contain but are not limited to containing the following information: (1) Primary directory number (described later herein); List of all directory numbers used to call terminals that are defined by the service profile; For each directory number defined in the profile, any special actions to be taken for calls to 2 that directory number service profile SP1 specifies audible alerting for DN1); S t20 List of digital subscriber lines on switch 1000 and USID values (described later herein); List of services and related data speed calling and speed call list); Data specifying the function of terminal feature buttons.

In the present example, user A subscribes to conflicting features. User A therefore requires multiple service profiles. User A requires one speed call list for terminals 2310 and 2320 and a different speed call list for terminal 2330.

Further, user A requires terminal 2330 to silently alert for calls to DN1 while terminals 2310 and 2320 audibly alert for calls to DN1. Thus, two service profiles are required, one profile for terminals 2310 and 2320 and another profile Sf..or terminal 2330.

Service profiles SP1, SP2, and SP3 are initially entered into block 100 of memory 3000 through service order requests when user A and user B establish ISDN service. Later changes to the service profiles, such as the addition of services, are made by service order requests and the data stored in block 100 of memory 3000 are updated. In addition, some data in the service profiles are updated by the initialization procedure discussed below.

L

1.

i 1 -8- The initialization procedure for relating a given terminal with a service profile stored in block 100 of memory 3000 is illustrated using terminal 2310. During the following initialization procedure, switch 1000 stores data in memory 3000 relating terminal 2310 on digital subscriber line 31 to service profile SP1 and assigns layer 3 address parameters to terminal 2310. The relationship created between terminal 2310 and service profile SP1, however, is only transitory. The initialization procedure is repeated when terminal 2310 undergoes terminal endpoint identifier removal or when other events described herein occur.

The service profile identifier (SPID), a terminal resident parameter, identifies the service profile describing the services subscribed for a terminal. In this exemplary embodiment, the service profile identifier consists of two fields: the primary directory number (PDN) and the primary directory number index.

However, other naming conventions may be used for the service profile identifier.

Each user has a unique primary directory number and all terminals with the same primary directory number belong to the same user. User A's primary directory number is DN1. User B's primary directory number is DN2. Although a single terminal may have several directory numbers, every terminal has a directory number that is considered its primary directory number. The primary directory number index is used in combination with the primary directory number to 20 identify a particular service profile when a user has multiple service profiles. This naming convention uniquely identifies a service profile over the entire switching system. Following this naming convention, the service profile identifier for user A's terminals 2310 and 2320 is (DNl:1). The service profile identifier for user A's terminal 2330 is (DN1:2). The service profile identifier for user B's terminals 2340 and 2410 is (DN2:1).

A network administrator provides service profile identifiers to a user when the user subscribes to the ISDN service. The service profile identifier for terminal 2310 is stored in a non-volatile memory block 600 (FIG. 3) of memory 7310 to retain the service profile identifier even if terminal 2310 loses power.

User A initializes or changes the service profile identifier by interacting with terminal 2310 in a local mode and entering the desired value into block 600. User A initializes the value of the service profile identifier stored in block 600 of memory 7310 to the primary directory number and primary directory number index for terminal 2310, (DN1:I).

-~14 ~P--YII~ .I i.l. I lii...l.li-- iii~l l -9- Either the switch or the terminal may invoke initialization. FIG. 4 shows the messages exchanged when the terminal invokes initialization while FIG.

shows the messages exchanged when the switch invokes initialization. Terminal 2310 invokes initialization by transmitting an initialization request containing its service profile identifier to switch 1000. Switch 1000 invokes initialization by transmitting a message to terminal 2310 requesting terminal 2310 to transmit its service profile identifier to switch 1000. This additional message is the only difference between switch invoked and terminal invoked procedures. When terminal 2310 receives a message from switch 1000 requesting that it transmit its SPID, terminal 2310 responds with the same message that it transmits to invoke initialization.

In the present example, terminal 2310 invokes initialization by transmitting a message to switch 1000 containing its service profile ir'ntifier, (DN1). In response to the message transmitted by terminal 2310, switch 1000 searches block 100 of memory 3000 for a service profile identified by (DN1). The search is successful and shows that service profile identifier (DN1) identifie; service profile SP1.

Next, switch 1000 assigns a user service identifier (USID) and a terminal identifier (TID) to terminal 2310. A USID, which in this exemplary 20 embodiment ranges in value from 0 to 255, is an addressing parameter used by switch 1000 in layer 3 messages. The global USID, 255, is used to address all terminals on a given digital subscriber line. A USID, a short version of the service profile identifier, uniquely identifies a service profile on a given digital subscriber line and is used to address all terminals with the same service profile.

The USID has significarce only on a given digital subscriber line while the service profile identifier has significance over the entire switch 1000. Although the USID is used as a layer 3 addressing parameter in this exemplary embodiment, the service profile identifier could be used as a layer 3 addressing parameter.

However, using the USID reduces the size of messages transm.tted between switch 1000 and terminal 2310. The TID, which in this exemplary embodiment ranges in value from 0 to 127, when combined with a USID identifies a specific terminal on a given digital subscriber line. The TID value of 127, referred to as the global TID, is used as a wild card value. A USID and TID parameter with the TID set to 127 addresses all terminals with the value specified i, the USID.

f L r~j~l -i To assign a USID to terminal 2310, switch 1000 first reads data stored in service profile SP1 to determine if a USID has been assigned on digital subscriber line 31 for service profile SP1. Service profile SP1 contains a relation defining digital subscriber line and USID pairs allocated for service profile SP1.

The relation is keyed by digital subscriber line and includes one non-key attribute, USID. Switch 1000 reads the relation using a key value of 31 corresponding to digital subscriber line 31, but finds no tuple with that key value. Accordingly, switch 1000 inserts a tuple, (31, into the relation in service profile SP1. This allocates a USID with value of 1 to service profile SP1 on digital subscriber line 31. Switch 1000 also inserts a tuple into a relation in a block 400 (FIG. 2) of memory 3000 that relates a digital subscriber line and USID to a service profile identifier. This relation is keyed by a compound key formed from digital subscriber line and USID and contains one non-key attribute, service profile identifier. Switch 1000 inserts the tuple (31, 1, DN1:1).

Switch 1000 assigns the terminal endpoint identifier for terminal 2310 as the value of the TID for terminal 2310. Switch 1000 obtains the terminal endpoint identifier from level 2 frames of the message sent from terminal 2310 to switch 1000. Other methods can be used to derive a unique TID and there is no requirement that the terminal endpoint identifier and the TID be the same.

20 Assigning the TID the value of the terminal .nIdpoint identifier is simple to implement and guarantees a unique value since all terminals on a digital subscriber line have unique terminal endpoint identifiers. The terminal endpoint identifier value for terminal 2310 is 65. Service profile SP1 contains a relation relating each (USID TID) pair for a given digital subscriber line to a terminal.

endpoint identifier. Switch 1000 inserts a tuple into this relation relating (1 on digital subscriber line 31 to a terminal endpoint identifier with value Next, switch 1000 stores the received service profile identifier, (DN1:1), in the data block 530 of memory 3000. This establishes a relationship between terminal 2310, identified by a digital subscriber line and terminal endpoint identifier pair, (31:65), and the service profile SP1, identified by the service profile identifier (DN1:1).

Switch 1000 transmits the assigned (USID:TID) pair, to terminal 2310 in a message on the point-to-point signaling link identified by the terminal endpoint identifier with value of 65. On receipt of this message, terminal 2310 stores the USID and ID in block 700 and block 800 (FIG. 3) respectively l i -11 of memory 7310. Terminal 2310 transmits a message to switch 1000 acknowledging receipt of the (USID:TID) pair.

A similar procedure is followed for initialization of user A's other terminals 2320 and 2330 as well as user B's terminals 2340 and 2410. Table 1 presents the parameters that exist after the above initialization procedure is completed for terminals 2310, 2320, 2330, 2340, and 2410.

USER USER USER USER USER USER "B" TERMINAL 2310 2320 2330 2340 2410 (DSL TEI) (31 65) (31: 87) (31 :76) (31 68) (41 (DSL: USID TID) (31:1 :65) (31:1:87) (31:7:76) (31:2:68) (41:7:65) SPID (DN1: 1) (DN1 1) (DN1 (DN2: 0) (DN2 0) Table 1 4 t S This example illustrates the association of more than one terminal with a single service profile and the location of terminals associated with the same service profile on the same digital subscriber line or on separate digital subscriber lines.

30 Since the relationship between a particular terminal and a given service profile is S not statically assigned at subscription time but is instead dynamically established by the above initialization procedure, a user may add terminals or move terminals between digital subscriber lines at the user's convenience.

The service profile information -fr this two user example is found in Table 2.

*1 St SERVICE PROFILE SPI SP2 SP3 SPID DN1:1 DN1:4

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12- DNs DNI-Aud. Alert DNI-Si, nt Alert for 20 sec. DN2-Aud. Alert (DSL: USID) (31 (31 (31 :2) (41 :7) (DSL:USID:TID:TEI) (31:1:65:65) (31:7:76:76) (31:2:68:68) (31:1:87:87) (41:7:65:65) SERVICES Speed Call List 1 Speed Call List 2 Table 2 Switch 1000 uses the USID and TID parameters assigned to terminals 2310, 2320, 2330, 2340, and 2410 to address individual terminals or groups of S 20 related terminals on digital subscriber lines 31, 41, and 51. To transmit a message to terminal 2310 on digital subscriber line 31, switch 1000 addresses the message with a (USID:TID) pair of (1 65). The (USID:TID) pair (1 65) uniquely f. t identifies terminal 2310 on digital subscriber line 31. Assume that switch 1000 transmits this message on digital subscriber line 31 using the broadcast terminal endpoint identifier, 127. Each of the terminals 2310, 2320, 2330, and 2340 will compare the USID and TID in the message with the USID and TID values stored in their memory. Terminal 2320 compares the USID and TID stored in memory 7320 with the USID and TID specified in the message. The USID matches but the TID does not match so terminal 2320 discards the message. Terminals 2330 and 2340 compare the USID and TID specified in the message with the USID and TID stored in their respective memories. The USID values do not match, so both terminals 2330 and 2340 discard the message. Terminal 2310, on the other hand, S< compares the USID in the message with the USID stored in block 700 of memory 7310 and determines that the values match. Terminal 2310 compares the TID in the message with the TID stored in block 800 of memory 7310 and determines that the values match. Thus, terminal 2310 processes the message.

To transmit a message to all terminals sharing a specific service profile on the given digital subscriber line, switch 1000 addresses the message with the USID identifying the specific service profile on digital subscriber line 31 and the global TID. Consider an example of switch 1000 sending a message to Ii~:I 13 all terminals for service profile SP1 on digital subscriber line 31. Service profile SP1 is identified on digital subscriber line 31 by a USID value of 1. Switch 1000 addresses the message with a (USID:TID) parameter of (1:127), corresponding to the specific USID and the global TID. Switch 1000 broadcasts this message on digital subscriber line 31 using the broadcast terminal endpoint identifier, 127.

When terminals 2330 and 2340 receive the message, they examine the (USID:TID) address parameter and determine that the USID specified is not the USID stored in their respective memories. Thus, terminals 2330 and 2340 discard the message. Terminal 2310 and 2320, however, both recognize the global TID and determine that the USID matches the USID stored in their respective memories. Since the message contains the global TID, terminal 2310 and 2320 do not perform any comparison on the TID. Both terminal 2310 and terminal 2320 process the message.

The USID and TID addressing scheme also allows switch 1000 to address all but one specific terminal associated with a given service profile. An octet is allocated in messages for the TID and an interpreter bit. The 7 low order bits in the octet are used to represent the TID, which ranges in value from 0 to 127, and the high order bit of the octet is used as the interpreter bit. When the interpreter bit is set to 0, as has been assumed in all the previous examples and all 20 other examples unless specifically stated, the terminals interpret the USID and TID *i address as illustrated by the examples above. When the interpreter bit is set to 1, terminals interpret the address as specifying all terminals with the indicated USID except the terminal specified by the TID. Consider the following example of transmitting a message to all terminals for service profile SP1 on digital subscriber line 31 except terminal 2320. Service profile SP1 is identified on digital subscriber line 31 by a USID value of 1. In preparing the message, switch 1000 sets the USID in the message to 1, sets the interpreter bit to 1, and sets the remaining 7 bits in the octet specifying the TID to the TID value of 87 corresponding to terminal 2320. Switch 1000 transmits the message on digital subscriber line 31 using the broadcast terminal endpoint identifier, 127. Since, as discussed in the above examples, the USID in the message does not match the USID for terminals 2330 and 2340, these terminals discard the message. Terminal 2320 compares the USID and TID specified in the message with the USID and TID stored in memory 7320. The USID and TID specified in the message match the corresponding values in memory 7320. Since the interpreter bit is set to 1 and t 14 the TID matches, the terminal recognizes that the message is not addressed to it and discards the message. Terminal 2310 compares the USID and TID specified in the message with the USID and TID stored in memory 7310. The USID matches but the TID does not match. Since the interpreter bit is set to 1, terminal 2310 processes the message.

The following examples illustrate the use of the USID and TID by switch 1000 in call processing. In these examples, user C, identified by primary directory number DN4, has one terminal 2510. User D, identified by primary directory number DN5, has three terminals 2520, 2530, and 2540. User E, identified by primary directory number DN6, has one terminal 2550. Each of the five terminals is located on digital subscriber line 51.

Assume that terminals 2510, 2520, 2530, 2540, and 2550 have completed the above initialization procedure and that the address parameters shown in Table 3 have been assigned.

o o 0 Io 0O 8* 0 o 00 4 tO O tE CrC C a

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25 USER USER USER USER USER USER "E" TERMINAL 2510 2520 2530 2540 2550 (DSL TEI) (51 :65) (51 :66) (51 :68) (51 :71) (51 :72) (DSL USID :TID) (51 1 65) (51 2 66) (51 2 68) (51 2 71) (51 3 72) SPID (DN4: 1) (DN5: 1) (DN5: 1) (DN5: 1) (DN6: 1) Table 3 Three service profiles SP4, SP5, and SP6 (FIG. 2) define the services subscribed to by these users. Each of the three service profiles SP4, SP5, and SP6 specify key system service. Key-system service allows each of the users C, D, and E to have multiple DNs and to share these DNs with the other users. For calls to DN4 and DN5, service profile SP6 specifies silent alerting followed in 18 seconds by audible alerting if the call has not been answered. Otherwise, audible alerting is specified in service profiles SP4, SP5, and SP6 for all directory numbers. Table 4 illustrates the service profile information for the following examples.

15 0 o t t 0 36 *0 I 6 Service Profile SP 4 SP 5 SP 6 SPID DN4:1 DN5:1 DN6:1 PDN DN4 DN5 DN6 DNs DN4-Aud. Alert DN5-Aud. Alert DN4-Silent Alert for 18 sec.

DN7-Aud. Alert DN7-Aud. Alert DN5-Silent Alert for 18 sec.

DN6-Aud. Alert DN7-Aud. Alert DN8-X.25 Packet (DSL USID) (51 1 (51: 2 (51 3 (DSL:USID:TID:TEI) (51:1:65:65) (51:2:66:66) (51:3:72:72) (51:2:68:68) (51:2:72:72) SERVICES Key System Key System Key System Feature 15 ACBC Buttons 0 It

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Cr 0

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00 O O 0 Table 4 Switch 1000 addresses an individual terminal when providing recall services such as automatic call back calling. For example, assume terminal 2510 invokes auto call back calling. When terminal 2510 invokes the service, switch 1000 saves the USID and the TID of *rminal 2510, To recall terminal 2510, switch 1000 broadcasts a SETUP message on digital subscriber line 51 addressed with the saved USID and TID, (1:65).

The next example illustrates use of the USID and TID addressing parameters in call offering. FIG. 6 is a diagram of the message flow between 40 switch 1000 and terminals 2510 and 2550 for this example. For an incoming call, switch 1000 uses the directory number mapping relation stored in block 200 of memory 3000 (FIG. 2) to map the called directory number to (DSL:USID) pairs corresponding to each digital subscriber line and service profile combination related to the directory number. Data is inserted in the directory number mapping 7ILiB=-~ .l i: I~ 16table through service orders when a user subscribes to a directory number. Table defines the directory number mapping table for the following examples. An asterisk denotes that the service profile in the corresponding column subscribes to the called directory number.

DN SP4 SP5 SP 6 DN4 DN6 DN7 DN8 Table S 25 When an incoming call arrives at switch 1000 for directory number DN4, switch 1000 reads the directory number mapping relation in block 200 of memory 3000 to determine all service profiles, identified by (DSL USID), that a o Q subscribe to directory number DN4. The (DSL USID) combinations determined are (51 1) and (51 Switch 1000 reads the service profiles associated with these (DSL USID) combinations to determine if the service profiles specify any special terminating treatment for calls to DN4. The service profiles associated with (51 1) and (51 3) are service profile SP4 and service profile SP6, respectively. Service profile SP4 specifies audible alerting for calls to DN4.

Service profile SP6 specifies silent alerting for 18 seconds for calls to DN4 t 35 followed by audible alerting.

CCITT Recommendation I.441/Q.931 requires that SETUP messages be broadcast using the broadcast terminal endpoint identifier. Switch 1000 offers S< the call to terminals associated with SP4 by broadcasting a SETUP message addressed with a (USID TID) address of (1 127) on digital subscriber line 51.

The SETUP message contains a call reference value of 3, a signal information element specifying audible alerting and a (USID:TID) pair of (1 127). The call reference value is used by switch 1000 to associate a series of messages.

i -17- Switch 1000 offers the call to terminals associated with service profile SP6 also by broadcasting a. SETUP message on digital subscriber line 51. This SETUP message contains a call reference value of 5, a signal information element specifying silent alerting, and an a (USID TID) pair of (3 127). Since the call is offered to both service profiles, distinct call reference values are used for each SETUP message so that switch 1000 can separate the resulting series of messages.

On receipt of the message addressed by the (USID TID) pair of (1 127), terminal 2510 recognizes the global TID in the message and compares the USID specified in the message with the USID stored in memory 7510. The USID matches so terminal 2510 sends an ALERTing message to switch 1000 and begins to audibly alert. Terminal 2550 also recognizes the global TID in the message and compares the USID specified in the message with the USID stored in memory 7550. The USID does not match so terminal 2550 disregards the message.

On receipt of the message addressed by the (USID TID) pair of (3 127), terminal 2510 recognizes the global TID in the message and compares the USID specified in the message with the USID stored in memory 7510. The USID does not match so terminal 2510 disregards the message. Terminal 2550 S recognizes the global TID in the message and compares the USID specified in the 0 °e 20 message with the USID stored in memory 7550. The USID matches so terminal 2550 sends an ALERTing message to switch 1000 and begins to silently alert.

°°For both SETUP messages, each of terminals 2520, 2530, and 2540 determine that the USID specified in the message does not match the USID stored in their respective memory and thus these terminals disregard both messages and 4 25 do not alert.

Finally, if the call is not answered within 18 seconds, switch 1000 sends an INFOrmation message to terminal 2550 containing a call reference value of 5 and a signal information element specifying audible alerting.

Notice in this example that switch 1000 addressed the SETUP messages on a service profile basis and did not send individual messages to each terminal. Thus, switch 1000 offers calls on a service profile basis without requiring data defining how many terminals are associated with a particular service profile. This illustrates the flexibility available to a user in adding or removing terminals without requiring a service order.

.LI 1 18 The next example defines the procedure used for an incoming call. Without the initialization procedures, permanent D-channel X.25 services including permanent virtual circuits as specified by CCITT Recommendations and X.31 could only be supported on subscribed-to fixed terminal endpoint identifiers. Permanent X.25 service requires the switch to deliver the Incoming Call packet to the proper D-channel packet link, designated by a specific terminal endpoint identifier. Switch 1000 associates the packet links with the appropriate service profile during the initialization procedure. This allows fixed and automatic terminal endpoint identifiers to be used for permanent D-channel packet services.

For example, when there is an incoming X.25 packet call to switch 1000 for destination address DN8, switch 1000 performs a DN mapping that produces the (DSL USID) pair (51 Since the X.25 packet call must be offered on a specific D-channel packet link specified by a terminal endpoint identifier, switch 1000 determines the (DSL TEI) pair. Switch 1000 reads the relation in block 400 (FIG. 2) of memory 3000 to determine that (DN6:1) identifies the service profile. Using this service profile identifier, switch 1000 searches the service profiles in block 100 (FIG. 2) of memory 3000 with the service profile identifier and retrieves service profile SP6. Switch 1000 reads data I20 in service profile SP6 and determines that the terminal endpoint identifier is 72.

Finally, switch 1000 offers an X.25 Call Request Packet on the D-Channel packet C t link associated with (DSL TEI) (1 72).

The following example shows switch 1000 using the interpreter bit.

FIG. 7 illustrates the message flow for this example. Terminal 2520 sends a SETUP message to switch 1000 to place an outgoing call using DN5. On receipt of this message, switch 1000 sends a SETUP ACK message to terminal 2520 on the point-to-point link identified by the terminal endpoint identifier for terminal 2520. Switch 1000 determines the USID and TID associated with terminal 2520.

Next, switch 1000 broadcasts an ASSOC message on digital subscriber line 51 to 30 all terminals that share DN5 to inform the terminals of the call origination. If switch 1000 were to broadcast the message to all terminals sharing service profile terminal 2520 would receive the message, recognize that the message was addressed to it, and process the message. Terminal 2520 would interpret the message to indicate that it could not originate a call on DN5. To eliminate this ambiguity, switch 1000 uses the interpreter bit to address the ASSOC message to j 1 ',t 19all terminals sharing service profile SP5 except terminal 2520.

Switch 1000 addresses the message using the USID and TID for terminal 2520, with the interpreter bit set to 1. Switch 1000 broadcasts this message on digital subscriber line 51. Switch 1000 does not have to send individual ASSOC messages to each terminal, but instead broadcast messages on a service profile basis. On receipt of the message, terminal 2530 and 2540 both recognize that the message is addressed to them and repond by sending ASSOCACK messages to switch 1000. Switch 1000 also sends an ASSOC message to all terminals sharing service profile SP6 since this profile also includes D5. Switch 1000 addresses this message using the USID for service profile SP6 and the global TID and broadcasts the message on digital subscriber line 51. On receipt of the message, terminal 2550 recognizes that the message is addressed to it and responds by sending an ASSOC_ACK message to switch 1000.

The final example has a terminal transmitting a message to switch 1000 to originate a call or to indicate the activation of some feature at the terminal. Here switch 1000 uses the DSL:TEI to service profile association that was recorded in the terminal endpoint identifier data blocks 500 at initialization to identify the service profile associated with the terminal. For example, assume user C invokes automatic call back calling by activating feature button 15 on terminal *20 2510. Terminal 2510 sends a message to switch 1000 indicating that feature button 15 was activated. The message from terminal 2510 contains the terminal S endpoint identifier, which has a value of 65, for terminal 2510. Switch 1000 reads data block 550 of memory 3000 to determine the service profile associated with the terminal endpoint identifier value of 65 on digital subscriber line 51. The service profile identifier specified is (DN4:1). Switch 1000 searches block 100 in memory 3000 for a service profile identified by the service profile identifier, (DN4:1). The service profile that switch 1000 retrieves is service profile SP4.

Data in service profile SP4 defines the service associated with the feature buttons on terminal 2510. Switch 1000 reads this data to determine the services associated with feature button 15. The data define feature button 15 as the button for automatic call back calling. Switch 1000 processes the request accordingly.

The following describes in greater detail the states that terminal 2310 and switch 1000 enter during initialization. First, the states and state transitions for terminal 2310 are discussed. Next, the states and state transitions for switch 1000 relating to terminal 2310 are discussed.

.I

l il l FIG. 8 illustrates the set of possible initialization state transitions for the terminals shown in FIG. 1. At any given time, each of the terminals shown in FIG. 1 is in one of four states, DOWN, Not Initialized (NOT-INIT), Awaiting Initialization (A-INIT), and Multipoint Initialized (M-INIT). For example, consider the state transitions made by terminal 2310, which represents the transitions made by each of the terminals 2310 through 2550. Terminal 2310 is in the DOWN state when it is powered down. It moves from this state to the NOT- INIT state on power up.

Terminal 2310 moves from the NOT-INIT state to the A-INIT state after transmitting a message containing its service profile identifier to switch 1000 requesting initialization. When power is turned off, terminal 2310 returns to the DOWN state.

If terminal 2310 receives a message from switch 1000 addressed by a USID-TID address parameter while terminal 2310 is in the A-INIT state, terminal 2310 discards the message and transmits a message to switch 1000 indicating that terminal 2310 requires initialization. Terminal 2310 moves from the A-INIT state to the NOT-INIT state when terminal endpoint identifier removal takes place at layer 2. When power is turned off, terminal 2310 returns to the DOWN state.

S Terminal 2310 moves from the A-INIT to the M-INIT state when the terminal has t 20 received a message from switch 1000 assigning a USID and TID pair to the terminal and has transmitted a message to switch 1000 acknowledging receipt of the USID and TID.

Terminal 2310 is in the M-INIT state following invocation and successful completion of initialization procedures. The only state from which terminal 2310 enters the M-INIT state is the A-INIT state. When switch 1000 requests reinitialization of the terminal while it is in the M-INIT state, terminal 2310 remains in the M-INIT state throughout the initialization procedures. If a message from switch 1000 containing a new USID and TID assignment is received when terminal 2310 is in the M-INIT state, no state change takes place and terminal 2310 transmits a message to switch 1000 acknowledging receipt of the USID and TID. When terminal endpoint identifier removal procedures take place at layer 2, terminal 2310 enters the NOT-INIT state. When power is turned off, terminal 2310 enters the DOWN state.

21 Terminal 2310 sends a message to switch 1000 to request initialization when any of the following events take place. Terminal 2310 establishes Layer 2 Terminal 2310 receives a message containing a USID-TID address while in the A-INIT state. Service profile identifier assignment or reassignment takes place at terminal 2310. Terminal 2310 receives a message from switch 1000 indicating an Initialization Request.

Terminal 2310 transmits the message requesting initialization once, and does not retransmit the message until a future occurrence of an event listed above. If terminal 2310 is in the NOT-INIT state, it moves to the A-INIT state after transmitting the message requesting initialization. If terminal 2310 is in the A-INIT or the M-INIT states, it does not change state.

FIG. 9 describes the set of possible state transitions for switch 1000.

At any given time, with respect to a particular terminal, switch 1000 is in one of five initialization states, NULL, Not Initialized (NGT-INIT), Wait for SPID JIT-SPID), Wait for USID-TID Acknowledgement (WAIT-USID-ACK) or Initialized (INIT). For example, consider the state of switch 1000 with respect to terminal 2310.

Switch 1000 is in the NULL state when terminal 2310 has not been t t assigned a terminal endpoint identifier value. Switch 1000 moves from this state 20 to the NOT-INIT state when a terminal endpoint identifier is assigned to terminal 2310.

,n 2. Switch 1000 is in the NOT-INIT state when terminal 2310 has been S assigned a terminal endpoint identifier value but has not been associated with a service profile in memory 3000 of switch 1000. Switch 1000 moves from the NOT-INIT state to the WAIT-SPID state after transmitting a message to terminal 2310 directing terminal 2310 to request initialization and send the terminal's service profile identifier to switch 1000. While in the NOT-INIT state, when switch 1000 receives a message from terminal 2310 requesting initialization and Scontaining a service profile identifier, switch 1000 assigns a USID-TID value to terminal 2310 and enters the WAIT-USID-ACK state. Terminal endpoint identifier removal at terminal 2310 results in switch 1000 moving from the NOT- INIT state to the NULL state.

Switch 1000 enters the WAIT-SPID state after it has sent a message to terminal 2310 directing the terminal to request initialization. After sending a message to terminal 2310 directing the terminal to request initialization, if switch

I-

-22- 1000 does not receive a response (an initialization request containing a service profile identifier parameter) from terminal 2310 within a predetermined time, switch 1000 retransmits the request once and remains in-the WAIT-SPID state. If switch 1000 does not receive a response to the retransmission after predetermined time, the switch will provide default service to the terminal as discussed below.

After receipt of the service profile identifier from terminal 2310 switch 1000 assigns a USID-TID value to terminal 2310, sends a message containing the USID-TID value to terminal 2310, and moves to the WAIT-USID- ACK state. The USID and TID values are assigned to the terminal based on the validity of the transmitted service profile identifier. If switch 1000 finds a service profile corresponding to the service profile identifier, switch 1000 transmits a message containing the corresponding USID and TID pair. If no corresponding service profile is found, switch 1000 transmits a message containing a USID and TID value that is associated with a default service profile on digital subscriber line 31. Associated with each digital subscriber line is such a profile specifying the default service for the digital subscriber line. Default service is determined as a subscription option on a digital subscriber line basis.

Switch 1000 moves to the WAIT-USID-ACK state after sending terminal 2310 a USID-TID value and awaits acknowledgement from terminal 2310 20 that it has received these parameters. On receipt of this acknowledgement, switch 1000 moves to the INIT state. When switch 1000 transmits a message to assign a S USID-TID value to terminal 2310, but does not receive an acknowledgement from the terminal within predetermined time, switch 1000 retransmits the message. If switch 1000 again fails to receive an acknowledgement from terminal 2310 within a predetermined time, switch 1000 considers this a protocol error and moves to the INIT state.

Switch 1000 is in the INIT state with respect to terminal 2310 when the terminal has been associated with a service profile in block 100 of memory 3000. Switch 1000 moves to the WAIT USID ACK state when terminal 2310 sends a different service profile identifier to the switch. Switch 1000 moves to the NULL state when terminal endpoint identifier removal occurs on the layer 2 link between terminal 2310 and the swich.

Switch 1000 sends a message to the terminal(s) on a digital subscriber line directing the terminals to request initialization in the following instances: 1. Switch 1000 detects too many errors in the TEI to (USID: TID) mappings for

MEMEMN.

23the digital subscriber line.

2. Switch 1000 has undergone an initialization procedure due, for example, to a power loss then restoral. In this instance, the switch controls the requests for initialization so as not to flood the switch.

3. As a periodic maintenance activity.

4. When switch 1000 detects that layer 1 comes up on the digital subscriber line.

To begin the initialization procedure, switch 1000 transmits a message via a point-to-point or the broadcast link to one or more terminals on the digital subscriber line. This message directs the terminal(s) to send a message to the switch requesting initialization and containing the terminal's service profile identifier. All initialized and uninitialized terminals terminals in the M-INIT, and the A-INIT or NOT-INIT states, respectively) that receive this message respond by transmitting an initialization request containing the service profile identifier parameter currently resident in the terminal's memory.

When terminal 2310 attempts to request service before completion of initialization procedures, switch 1000 buffers the request for processing after switch 1000 has established the service profile relationship.

t I tt

Claims (10)

1. A call service initialization method for a switching system, for use in a digital network supporting integrated voice and data facilities, said switching system connected via a single digital subscriber line to a plurality of terminals, said switching system comprising means for storing a plurality of service profiles each defining a set of call services, said method comprising said switching system receiving from one of said plurality of terminals on said line a first identifier defining said one terminal and a second identifier defining one of said plurality of service profiles, in response to receipt of said first and second identifiers, said switching system enabling for said one terminal a set of call services defined by said one service profile, in response to receipt of said second identifier, said switching system determining a third identifier distinguishing said one service profile from any other service profiles defining sets of call services enabled for ones of said plurality of terminals, and, after determining said third identifier, said switching system transmitting said third identifier to said one terminal and thereafter addressing said one terminal using said third identifier. A method in accordance with claim 1, wherein said single t "cdigital subscriber line comprises a broadcast link and a plurality of point-to-point links, each of said point-to-point links being between said switching system and a different one of said plurality of terminals, said method further comprising after said transmitting step and in response to an incoming call, said switching system tranmitting on said broadcast link of said single digital subscriber line a first message concerning said call, said message addressed by said third identifier, i-I t .7 after transmitting said first message, said switching system receiving a second message on the one of said point-to-point links between said switching system and said one terminal,and, in response to receipt of said second message, said switching system communicating with said one terminal concerning said incoming call using the point-to-point link on which said second message was received.

3. A method in accordance with claim 1, further comprising in response to said receipt of said second identifier, said switching system determining a fourth identifier distinguishing said one terminal from any other ones of said plurality of terminals for which said set of call services defined by said one service profile is enabled, and, after determining said fourth identifier, said switching system transmitting said fourth identifier to said one terminal and thereafter addressing said one terminal using said third and fourth o identifiers. 0 4. A method in accordance with claim 3 where said first and fourth identifiers are identical. o o

5. A method in accordance with claim 1, further comprising said switching system receiving from another of said terminals on said line an identifier defining said another terminal and an identifier identical to said second identifier defining said one service profile, in response to receipt of said identifier defining said another m00 terminal and said identifier identical to said second identifier, said switching system enabling for said another terminal said set of call services defined 3y said one service profile, and, in response to said receipt of said identifier identical to 30 said second identifier and after determining said third identifier, said switching system transmitting said third identifier to said another terminal and thereafter addressing said another terminal using said third identifier.

6. A method in accordance with claim 1; further comprising said switching system receiving on said line an identifier defining another of said plurality of terminals and an identifier identical to said second identifier defining said one service /f 'a profile, 26 in response to receipt of said identifier defining said another terminal and said identifier identical to said second identifier, said switching system enabling for said another terminal said set of call services defined by said one service profile, in response to said receipt of said second identifier, said switching system determining a fourth identifier distinguishing said one terminal from any other ones of said plurality of terminals for which said set of call services defined by said one service profile is enabled, after determining said fourth identifier, said switching system transmitting said fourth identifier to said one terminal and thereafter addressing said one terminal using said third and fourth identifiers, in response to said receipt of said identifier identical to 15 said second identifier, said switching system determining a fifth identifier distinguishing said another terminal from any other ones of said plurality of terminals for which said set of call services defined, by said one service profile is enabled, and, r after determining said third and fifth identifiers, said switching system transmitting said third and fifth identifiers to said another terminal and thereafter addressing said another terminal using said third and fifth identifiers.

7. A method in accordance with claim 6 further comprising after trasmitting said third and fourth identifiers to said one terminal and sa1iO third and fifth identifiers to said another terminal, said switching system addressing said one and said another terminal collectively using said third identifier and a predefined, global identifier.

8. A method in accordance with claim 6 further comprising after cransmitting said third and fourth identifiers to said one terminal and said third and fifth identifiers to said another terminal, said switching system addressing said one terminal using said third and fifth identifiers in combination with an interpreter field.

9. A method in accordance with claim 1; further comprising said switching system receiving on said line a sixth 27 27 identifier defining another one of said plurality of service profiles and a seventh identifier defining another one of said plurality of terminals, in response to receipt of said sixth and seventh identifiers, enabling for said another terminal a set of call services defined by said another service profile, in response to said receipt of said sixth identifier, said switching system determining an eighth identifier distinguishing said another service profile from any other service profiles defining sets of call services enabled for ones of said plurality of terminals, and, after determining said eighth identifier, said switching system transmitting said eighth identifier to said another terminal 000, and thereafter addressing said another terminal using said eighth ooo 15 identifier. 0000

10. A method in accordance with claim 1, further comprising 00 0o said switching system receiving on said line a sixth Sa identifier defining another one of said plurality of service 0* .profiles and a seventh identifier defining another one of said plurality of terminals, in response to receipt of said sixth and seventh identifiers, enabling for said another terminal a set of call services defined by Owl r Col said another service profile, 04 9 1 0"t after enabling said set of call services defined by said one service profile for said one terminal and said set of call services ,r defined by said another service profile for said another terminal, said switching system addressing said one and said another terminal collectively using a predefined, global identifier defining all service profiles defining sets of call services enabled for ones of said plurality of terminals.

11. A method in accordance with claim 1, wherein said storing means stores directory number data associating a plurality of directory numbers with said plurality of service profiles, wherein said line comprises a broadcast link and a plurality of point-to-point links, wherein said first identifier ICE

28- defines one of said point-to-point links, wherein said enabling step comprises writing link data to said storing means defining said one point-to-point link as being associated with said one service profile, and wherein said method further comprises the following steps in sequence: after said enabling step and in response to an incoming call for one of said plurality of directory numbers, said switching system reading said directory number data and determining that said one service profile is associated with said one directory number, said switching system reading said link data and determining that said one point-to-point link is associated with said one service profile, said switching system transmitting on said one point-to-point link a message concerning said incoming call, and said switching system communicating with said one terminal on .999 15 said one point-to-point link concerning said incoming call. :o 12. A method in accordance with claim 11 wherein said message o comprises an X.25 call request packet. S,13. A method in accordance with claim 11 further comprising before said receiving step, said switching system assigning said first identifier to said one terminal and transmitting said first identifier to said one terminal. 4.4' 14. A call service initialization method for a terminal, fsupporting integrated voice and data facilities, said terminal connected to one or more other terminals via a single digital subscriber line to a switching system for use in a digital network supporting integrated voice and data facilities, said switching system including means for storing a plurality of service profiles each defining a set of call services, said method comprising i said terminal transmitting on said line a first Identifier defining said terminal and a second identifier defining one of said plurality of service profiles, after said transmission of said first and second identifiers, said terminal cooperating with said switching system to provide a set of call services defined by said one service profile, after transmitting said second identifier, said terminal N~jk4 29 receiving a message containing a third identifier distinguishing said one service profile from any other service profiles defining sets of call services enabled for ones of said plurality of terminals, and, in response to receipt of said third identifier, said terminal responding to messages addressed by said third identifier. A switching system, for use in a digital network supporting integrated voice and data facilities, connectable via a single digital subscriber line to a plurality of terminals, said system comprising means for storing a plurality of service profiles each defining a set of call services, and control means for controlling said switching system to provide call services for said plurality of terminals, wherein said control means is responsive to receipt of a first identifier from one of a plurality of terminals defining said one terminal and a second identifier defining one of said plurality of service profiles, for enabling for said one terminal a set of call services defined by said one service profile, and is further responsive to receipt of said second identifier, for determining a third identifier distinguishing said one service profile from any other service profiles defining sets of call services enabled for ones of said plurality of terminals, and, after determining said third identifier, for transmitting said third identifier to said one terminal and thereafter addressing said one terminal using said third identifier. CSTB/BG 1 -17 30 16. A call service initialization method substantially as hereinbefore described with reference to the drawings. 17. A switching system substantially as hereinbefore described with reference to the drawings. 41 a. 4 ?0 0 it r DATED this TWENTY THIRD day of FEBRUARY 1990 American Telephone and Telegraph Company Patent Attorneys for the Applicant SPRUSON FERGUSON gr/1651F '9 r'