GB2075306A - Improvements in or relating to electronic intercommunication installation - Google Patents

Abstract

There is provided an electronic intercommunication installation which comprises a central unit 1 connected to a plurality of intercommunication terminals 2, 3 by a first star scheme comprising three connection pairs per terminal. The control unit is connected to a plurality of external lines 4, 5 by a second star scheme. <IMAGE>

Description

SPECIFICATION Improvements in or relating to electronic intercommunication installations The invention relates to an electronic intercommunication installation.

Intercommunication intallations both of the mechanical type and of the semi-electronic type are already known. Such known installations, whether they are of the mechanical type or of the semielectronic type, always comprise a connection system requiring large numbers of cables. The connection system extends either between the different stations or between the stations and a central unit.

Three connection methods are known for such installations. The first connection method consists of a series connection system, and is limited to an installation comprising seven stations. The second connection method is a star connection system with respect to the central unit. This connection method is limited to installations of medium and large capacity, i.e. installations comprising between ten and twenty stations. The third connection method is a connection system in which the various stations are connected in parallel. This connection system is used in particular for installations of medium capacity, and requires a maximum number of wires.

According to the invention there is provided an electronic intercommunication installation comprising a central unit connected to a plurality of universal intercommunication terminals by way of a first star scheme limited to three connection pairs per terminal and to a plurality of external lines by way of a second star scheme.

It is thus possible to provide an installation which can be used equally well for small capacities comprising for example two external lines and three or four internal stations, and for medium or large capacities of the order of eight external lines and sixteen internal stations, while utilizing a star wiring system limited to three connection pairs per station.

The invention will be further described, by way of non-limiting example, with reference to the accompanying drawings, in which: Figure 1 is a block diagram of an electronic intercommunication installation constituting a preferred embodiment of the invention; Figure 2 is a block diagram of an intercommunication terminal; Figure 3 is a block diagram of the central unit.

Reference will be made to Figure 1.

The electronic intercommunication installation is arranged in accordance with a star scheme, and comprises a central switching unit 1, to which a certain number of terminals 2,3 and a certian number of external lines 4, 5, are connected.

The central switching unit 1 is common to all the terminals 2,3 of a given installation, and its capacity corresponds to the equipment chosen. It can be extended by adding insertable printed-circuit boards, and, interalia, comprises a spacial speech connection network, external line interfaces, subscriber line interfaces, a control unit for the assembly, and a power supply unit for the installation.

In general, the electronic intercommunication installation comprises universal intercommunication terminals provided, ss standard operating features, with at least one external line connection, at least one local communication system and the facility for a call originating from an external line. According to a further embodiment, the terminals could equally comprise an amplified reception system and dialling without unhooking, and other additional operating features.

Reference will be made to Figure 2.

Each terminal is connected by three pairs 6,7 8 each comprising two wires. The pairs 6,7,8 each comprising two wires. The pairs 6,7,8 provide the connection between the terminal 2 and the central unit 1.

The various functions of the terminal 2 are provided for by a conversation circuit 9. This conversation circuit provides for speech transmission between the terminal 2 and the conversation line 6. It equally provides connection to an amplifier in the case of amplified reception.

Moreover, each terminal 2 comprises a control member 10 provided with a microprocessor 11. The microprocessor 11 is served by keys 12. Each key operation is recorded by the microprocessor and is transmitted to the central unit 1 by way of the control pair 7. In addition, the microprocessor 1 controls luminous signalling devices 13 by way of a control element 14 or sound signalling devices 15. The central unit 1 decides which signalling devices to operate, and gives the command to the microprocessor 11 to process the information received through the control pair 7 and to control the corresponding signalling device. Thethird pair 8 provides for power supply to the control member and connection member of the terminal. The power supply is effected by way of a regulator 16 from a 12 Volt supply through the two wires of the supply pair 8.

In addition, the terminal comprises a "basic station" printed-circuit board. The following functions can be effected by means of this board, namely: control and administration provided by the microprocessor 11; connection to the central unti by way of the pair 7; connection to the various signalling members 13 and to the keys 12; conversation organised around an electronic transmission circuit; call sound reception either by means of the buzzer 15 or by call ringing amplified over the loudspeaker.

An output signal from the terminal enables an external call strengthening device to be controlled.

The "basic station" printed-circuit board is supplied at 5 Volts generated from the 12 Volts of the supply pair 8 by way of the regulator 16. The use of components based on CMOS technology allows low power consumption to be obtained. The microphone power for the conversation circuit 6 is supplied from the central unit 1 by way of the conversation pair 6.

The printed-circuit board for the signalling mem bers comprises a printed circuit supporting the vari ous keys 12 and signalling members 13, the keys 12 being of the magnetic return type.

The amplified reception system can form part of the basic equipment of the station, and may replace the call buzzer 15. The system comprises an amp lifier, a call oscillator, a loudspeaker and three control potentiometers, one of which varies theconversation level by way of the amplifier and loudspeaker, and the other two of which act on the call reception system. The amplified reception system is connected by a stop-start switch.

Reference will now be made to Figure 3.

The central unit 1 comprises a control unit 17 which undertakes the general control of the entire intercommunication installation. At all times, the central unit knows the exact state of all terminals of the installation. For this purpose, it comprises a microprocessor 18, a connection network 19 and a tone generator 20. Likewise, the central unit comprises printed-circuit interface boards 21,22 for the external lines 4, 5. The central unit 1 also comprises printed-circuit interface boards 23,24 for the various terminals 2,3. In addition, the central unit can be provided with an integrated general power supply unit 25 comprising a charger 26 and associated battery 27. The rated operating voltage of the installation is 12 Volts.By virtue ofthe CMOS technology used both in the terminals 2,3 and in the central unit 1, the energy consumption of the installation is very low.

The control unit 17 supports the entire data part of the installation and comprises the microprocessor 18, read only memories (ROM) and random access memories (RAM). The design uses CMOS and TTL LS technology. The circuits are supplied at 5 Volts.

The connection is by means of HALF-DUPLEX synchronous data transmission. The control unit 17 also provides the commands for the various types of interface 21,22 for the external lines 4 and 5. These interfaces can be of decimal pulse diailing type, mule tifrequency tone type or other types. The commands can effect various functions such as looping, dialling, train function, reception of external calls, multifrequency, charging, emission of background music etc., and in addition the control unit provides a validity test for the operation of the central unit 1.

The tone is provided by a generator. The various rhythms are controlled by the microprocessor 18, and injected into the terminals 2,3 by way ofthe connection network 19. This connection network is of the one-wire switching type and is contralled by the microprocessor. It consists of a decoding and addressing circuit together with the actual, connection matrix. The network can be extended according to the number of terminals and external lines.

The base unit consists of a matrix provided with a decoding section and incorporated memories. The connection network 19 enables any interface 21,22 of the external lines 4,5 to be connected to any sub scriber interface 23, 24 of the terminals 2, 3. The connection network 19 likewise enables any subscriber interface 23, 24 to be connected to another subscriber interface by means of private circuits 30.

Oneofthe private circuits is reserved for the service station and is known as the service line 31.

The subscriber line interface 23,24, reduced to its most simple terms, is the normal unit between a subscriber terminal 2,3 and the intercommunication installation. The interface provides for power supply to the terminal 2,3 and for the dialogue between the terminal and the central unit 1, and comprises the following elements: the actuai. line interface which provides for the supply and adjustment of the conversation current to the termieral; the series Invention system for dialogue between the terminal and the central unit.

The subscriBer lirie interface 23, 24 consists of a translator and a current supply and adjustment circuit for the elecfronic transmission circuit of the station. This circuit is supplied with 12 Volts. The connection system for the exchange of information between the central unit I andaterminal is a system based on HALF-DUPLEX synchronous data transmission. This circuit is supplied with 5 Volts. As the 12 Volt supply is also provided for supplying the terminal associated with the interface 23,24, a protection device is provided at the interface 23, 24.

The external line interface is the normal connection unit between an external line and the intercommunication installation. It is reduced to its most sim ple terms. The equipment consists of the following elements: a connection interface adapted to the external line; a control and monitoring circuit.

The connection interface enables the transmission characteristics to be respected, while the control and monitoring circuit provides for connection between the external line and the control unit.

The mechanical part of the central unit is divided into several sub-assemblies 28,29. One of the subassemblies 29 comprises the general power supply unit 25, the control unit 17,,the connection network 19, the tone generator 20 and all ancillary equipment.

The or each other sub-assembly 28 comprises removable sockets fitted with the subscriber interfaces 23,24 and therexternal line interfaces 21,22.

These sub-assemblies are hooked to a frame which serves both as a supportforthe sub-assemblies and as a lead-in and passage surface for the connection cables.

In general, theterminals 2,3 and the external lines 4, 5 are directlyconnected to the subscriber interface boards 23,24 andiortothe interface boards 21, 22 for the external lines by means of connectors. The connection wiring for the sub-assemblies is made by means of a mother board into which the various subscriber interface boards 23,24 andlor the external line interface boards 21,22 are inserted. This mother board is connected to the control unit 17.

Claims (13)

1. An electronic intercommunication installation comprising a central unit connected to a plurality of universal intercommunication terminals by way of a first star scheme limited to three connection pairs per terminal and to a plurality of external lines by way of a second star scheme.

2. An installation as claimed in claim 1, in which the central unit comprises two sub-assemblies, one of which is provided with respective interfaces for the terminals and with respective interfaces for the external lines, and the other of which comprises interconnection and connection elements.

3. An installation as claimed in claim 2, in which the other sub-assembly comprises a connection network, a control unit, an integrated general power supply unit and a tone generator.

4. An installation as claimed in claim 3, in which the connection network is extendable according to the number of terminals and external lines and comprises inputs for the interfaces for the external lines, connections for the terminals, at least one private circuit, at least one service line, and inputs for the tone generator.

5. An installation as claimed in claim 3 or4, in which the control unit comprises at least one microprocessor and read only and random access memories adapted to the use of the installation.

6. An installation as claimed in any one of claims 3 to 5, in which the integrated general power supply unit comprises a charger and a low capacity battery.

7. An intallation as claimed in any one of claims 3 to 6, further comprising a frame which serves as a support both for the sub-assemblies and for connection wiring.

8. An installation as claimed in any one of claims 2 to 7, further comprising a direct connection between the terminals and the external lines by way of printed-circuit subscriber interface and external line interface boards by means of connectors.

9. An installation as claimed in any one of the preceding claims, in which connection wiring is effected by means of a mother board into which are inserted printed-circuit subscriber interface boards, external lines and the control unit, the mother board being connected to a or the integrated general power supply unit.

10. An installation as claimed in any one of the preceding claims, further comprising a microprocessorwhich is adapted to, and extendable in relation to, the applicational requirements of the installation both in terms of a or the control unit of the central unit and in terms of the terminals.

11. An installation as claimed in any one of the preceding claims, in which the central unit and the terminals comprise means for checking operation of the central unit and terminals.

12. An installation as claimed in any one of the preceding claims, in which control connection between the central unit and the terminals is based on half-duplex synchronous data transmission.

13. An electronic intercommunication installation substantially as hereinbefore described with refs pence to and as illustrated in the accompanying drawings.