AU651202B2

AU651202B2 - A key telephone system

Info

Publication number: AU651202B2
Application number: AU16313/92A
Authority: AU
Inventors: Gerd Siegmund
Original assignee: Alcatel NV
Current assignee: Alcatel Lucent NV
Priority date: 1991-05-25
Filing date: 1992-05-14
Publication date: 1994-07-14
Anticipated expiration: 2012-05-14
Also published as: EP0515966A2; EP0515966A3; AU1631392A; DE4117118A1; NZ242659A

Description

65120 P/00/011 28/5/91 2 Regulaton 3.2

AUSTRALIA

Patents Act 1990 9*#99* 9 9 4* .9.

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ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 95959* 991.

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99 *e Invention Title: "A KEY TELEPHONE SYSTEM" The following statement is a full description of this invcntion, including the best mcthocl of performing it known to us:t a 2 This invention relates to a key telephone system, in particular a group or executive/secretary system with several subscriber subsets which are interconnected via a bus, with at least one subscriber subset able to be connected to an exchange line or a private automatic branch exchange.

Such a key telephone system is known from TN-Nachrichten 1982, Vol. 84, pages 3 to 15 "Die neuen TN-Reihenanlagen TR 40 aus der Systemfamilie T With this known key telephone system, the individual subscriber subsets are connected to a central control unit which in turn is connected to one or more public exchange lines, or to an extension line as a secondary branch exchange. The central 10 control unit is provided with a central controller, consisting of microprocessor, a programmable ROM and a read-write memory; in addition, it is provided with a matrix-like switching network and with key-telephone and public-telephone subscriber circuits, wit the latter subscriber circuits being connected to the individual subscriber apparatus by separate four-wire lines. The bus interconnecting the subscriber subsets is provided within the central control unit.

Since such a key telephone system requires a central control unit, equipped with the above mentioned components, the costs associated with the manufacture of this central control unit and its installation and cabling to the individual subscriber subset are relatively high. Although such a key telephone system can be adapted for different sizes, this always requires, in addition to extra subscriber subsets, a rearrangement of the central control unit by substitution of the relevant printed circuit boards, and by insertion of additional ones.

An object of the present invention is to provide a key telephone system which avoids the need for a central control unit but can nevertheless be readily adapted to very different requirements such as differing subscriber subset types, operating characteristics for each type, etc.

According to the invention there is provided a key telephone system with several subscriber subsets which are interconnected via a bus, with at least one subscriber subset able to be connected to an exchange line or a private automatic branch exchange, wherein said bus provides a full-duplex interconnection for the individual subscriber subsets, the subscriber subsets, which are identical in the basic version, being provided with a microprocessor and an operating circuit, controlled by the microprocessor, which is arranged to carry out all functions allocated to the subscriber subsets, and wherein plug-in modules ara provided for one or more of the subscriber subsets for the actual execution of designated functions.

The significant advantage of the key telephone system according to the invention lies in the fact that no central control unit is necessary. Because of the decentralisation of the control, memory, switching and similar functions, the cost of interconnecting the individual subscriber subsets is also minimised. The assignment of desired operating characteristics, as well as the modification of the subscriber subset into a given type of equipment, can be achieved in the subset itself, in a simple manner and without affecting other equipment, by selecting one or more plug-in modules of a suitable kind, and the arrangement can subsequently be easily extended or reduced. A subsequent increase in the number of subscriber subsets is also possi- 10 ble, without affecting the other subscriber subsets which already exist.

Preferably the plug-in modules act as external or internal interfaces, the former meaning that the relevant subscriber subset is able to be connected to an exchange line or private branch exchange, while the latter means that the relevant subscriber subset is designed as a special purpose equipment or can have an auxiliary device connected. For example, a subscriber subset in the form of an ordinary telephone can in this way be converted into a cordless telephone, or a facsimile machine, etc. In both these cases, in addition to the plug-in module, an appropriate terminal is used as an auxiliary instrument with the relevant subscriber subset. An additional advantage is gained in the fact that the relevant auxiliary instrument and plug-in module can be exchanged between different subscriber subsets, and thus remain mobile.

Preferably, to enhance the internal functions of the subset, a chip card may be inserted therein by means of which a speech memory can be provided for telephone answering functions. With the aid of such a chip card, it is also possible to provide personal operating functions such as, for example, follow-on call switching, repeated dialling, calling-number indication, etc. Such operating characteristics can be easily extended or removed at any time.

Further particulars of the invention are contained in the following description, in which the invention is described in more detail with the aid of the design examples shown in the diagrams.

Figure 1 shows a schematic representation of the internal structure of a key telephone system in accordance with one design example of the invention; and Figures 2A-2C show examples of configurations of a key telephone system equipped with several subscriber subsets of different types.

The key telephone system 11 displayed in the diagram with different variations, is particularly suited to systems of small to medium size, for example group or

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4 executive/secretary systems. The key telephone system 11 contains several subscriber subsets 12 which are identical in their basic form. The subscriber subsets 12 can be externally styled in the customary way, that is they consist of a housing 13 into which are mounted a keyboard 14 and display 15, and onto which a handset 16 can be placed.

As shown in Figure 1, each subscriber subset 12 is equipped internally with an (ASIC) function circuit 17 which provides all intended subset functions, a microprocessor 18 connected to the function circuit 17, a memory unit 19 for control which 1 is connected to the microprocessor 18 and can, for example, consist of a programma- 10 ble ROM and a read-write memory, and a D/A converter 20 which is connected on one side to the function circuit 17 and on the other side to the handset 16. Furthermore, each subscriber subset 12 is provided with (here) two plug-in receptacles 21 and 22 fitted with contact sockets 23 and 24 which are connected to the function circuit 17. On a part of the housing 13 away from the plug-in receptacles 21 and 22 there is a card receptacle 26 whose reading elements 27, 27' are connected to the memory uinit 19 and the microprocessor 18 or to the function circuit 17.

Each of the subscriber subsets 12 is provided with two connection lines (input and output) 28, 29 which at one end are connected to the function circuit 17 and at the other end can be connected to a bus 30 which is provided for interconnection between the individual subscriber subsets 12. This bus 30 is designed as an internal full-duplex interconnection system which uses PCM channels for transmitting both **useful data and control signals.

As can be seen in Figure 1, the plug-in receptacles 21 and 22 can have plug-in modules 31 and/or 32 inserted. Very different methods of operation result for the subscriber subsets 12, depending on the plug-in modules 31 or 32 inserted, which act respectively as external or internal interfaces for an external network (public network, private branch exchange) or for auxiliary equipments. If, as shown for subscriber subset 12/3 in Figure 1, neither of the plug-in receptacles 21, 22 is equipped with a plug-in module 31, 32, an ordinary telephone set 12/3 results which can only communicate with the other subscriber subsets 12 of the key telephone system 11, ie. can only communicate internally. If the plug-in module 31 is used in the plug-in receptacle 21, then, as demonstrated by subscriber subsets 12/1 and 12/2, these subscriber subsets are connected via leads a and b to, for example, an exchange line. It is, however, also possible to connect the relevant subscriber subset to a larger, possibly higher-level, private branch exchange. In any case, this plug-in module 31, designed as an exchange connection module, permits an external connection for the relevant subscriber subset. If a particular type of plug-in module 32 is used in the plug-in receptacle 22, the equipment type of the subscriber subset 12 can be correspondingly modified. For example, as demonstrated by subscriber subset 12/1, this plug-in module 32, designed as a subscriber circuit, can be designed in such a way that it becomes possible to connect a facsimile machine 33 to subscriber subst 12/1 via leads a' and In this way the subscriber subset 12/1 functionally becomes a facsimile machine. A different type of plug-in module 32' is provided in subscriber subset 12/2, one that enables a cordless telephone to be used in the relevant area.

10 As shown in Figure 1, an additional subscriber terminal 36 is provided in the form of a base station for a mobile telephone, the base station being connected to the bus It is also possible, but not shown in Figure 1, to equip subscriber subset 12 with two identical plug-in modules 31 in order to provide the subscriber subset with, for example, two independent exchange lines or an exchange line and a line to a private branch exchange. A similar possibility exists regarding plug-in module 32. Furthermore, it is possible, but not shown in Figure 2, to provide the subscriber subset 12 with more than two plug-in receptacles.

Into the card receptacle 26 of every subscriber subset 12 a chip card may be inserted, which represents a program memory and which can be provided with widely differing programs. At least one of these chip cards 34 contains a memory section with the central programming code for the key telephone system 11, assigned to the reading element 27. In addition, it is possible to provide the chip cards with further memory sections, assigned to the reading clement 27', in order to provide the relevant subscriber subset 12 with additional operating characteristics. For example, if the chip card contains a speech memory section, it is possible to provide the subscriber subset 12 with a telephone-answering function. It is also possible to provide operating functions such as telephone number storage, repeated dialling, follow-on call switching, conference calls, etc. It is clear that the single chip card can also be divided into two or more chip cards.

With the aid of Figures 2A, 2B and 2C, examples of configurations of the key telephone system 11 are described which result from the varied use of the plug-in modules 31 and/or 32. For example, the key telephone system 11 A of Figure 2A consists of a total of four subscriber subsets 12, with two subscriber subsets 12/4 equipped with an exchange-connection plug-in module 31 and connected to a local I I exchange or private branch exchange 37, while the other two subscriber subsets 12/3 are only equipped for internal system communication. The key telephone system 1 1B of Figure 2B also consists of four subscriber subsets 12/4 which are all equipped for exchange connection, that is with the plug-in module 31. The key telephone system 11C of Figure 2C has a total of five subscriber subsets 12 of which two are exchange-connected subscriber subsets 12/2 with a cordless handset, one subset 12/1 is arranged as a facsimile machine, a fourth subset 12/3 is only capable of internal system communication and the fifth terminal 36 is equipped to be a base station for a mobile telephone.

10 It is clear that, apart from the equipment types and operating functions deb g m scribed, plug-in modules and chip cards with additional technical and functional .o: possibilities can be utilised.

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Claims

1. A key telephone system with several subscriber subsets which are interconnected via a bus, with at least one subscriber subset able to be connected to an exchange line or a private automatic branch exchange, wherein said bus provides a full-duplex interconnection for the individual subscriber subsets, the subscriber subsets, being provided with a microprocessor and an operating circuit, controlled by the microprocessor, which is arranged to carry out all functions allocated to the subscriber subsets, and wherein plug-in modules are provided fQr one or more of the subscriber subsets for the actual execution of designated functions.

2. A key telephone system as claimed in claim 1, wherein the plug-in module forms an external interface.

3. A key telephone system as claimed in claims 1 or 2, wherein the plug-in module forms an internal interface.

4. A key telephone system as claimed in any one of claims 1 to 3, wherein the subscriber subset has at least two receptacles for plug-in modules.

A key telephone system as claimed in any one of claims 1 to 4, wherein at least one chip card is provided for insertion into the subscriber !:bset to enhance said subsets operating functions.

6. A key telephone system, substantially as herein described with reference SI to Figures 1 2 of the accompanying drawings. DATED THIS FOURTH DAY OF MAY 1994 ALCATEL N.V. *gi. "ogo g a a.• go .go ABSTRACT A key telephone system (11) for use as a group or executive/secretary system is described which consists of several subscriber subsets (12) interconnected via a bus of which at least one subscriber subset (12) can be connected to an exchange line or a private automatic branch exchange. The bus (30) forms an internal full-duplex interconnection system between the individual subscriber subsets The sub- scriber subsets which are identical in the basic version, are provided with a microprocessor (18) and an operating circuit (17) (controlled by the microprocessor) which is designed to carry out all the functions allocated to the subscriber subsets For the actual execution of particular functions, plug-in modules (31, 32) are provided as external and/or internal interfaces for one or more of the subscriber sub- sets In this way, the key telephone system can operate without a central control unit and it can be readily adapted to very different requirements such as subscriber equipment type, operating characteristics of the relevant equipment type, etc. S Figure 1.