GB2105950A

GB2105950A - Telephone data interface

Info

Publication number: GB2105950A
Application number: GB08123998A
Authority: GB
Inventors: David William Askew; David Mullinger
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC
Priority date: 1981-08-06
Filing date: 1981-08-06
Publication date: 1983-03-30
Also published as: GB2105950B

Abstract

A telephone subscriber's terminal is provided which is connected to a line to a telephone exchange, e.g. a PABX, and also connected to a computer, when the terminal is in use. It also has access to a remote control unit (8). Thus it can function as a telephone, or as a computer interface, or both. When functioning as a computer interface, conversion (4, 5) is provided between the digital format used by the computer and the format used over telephone lines, usually MF. <IMAGE>

Description

SPECIFICATION Telephone data interface This invention relates to a telephone subscriber's terminal, which is usable both as a telephone and as a computer terminal.

According to the present invention there is provided a telephone subscriber's terminal which when in use is connected both to a telephone exchange and to a digital device such as a computer, which terminal includes telephone call-making and receiving equipment for making calls to the telephone exchange and for receiving calls therefrom, a telephone interface which when the terminal is in use is between the terminal's equipment and a line to the exchange, a data interface which when the terminal is in use is between the terminal and the digital device such as the computer, and control means whereby the terminal can be used as required as a computer terminal or as a telephone instrument, and whereby intelligence from the computer can be transmitted over the telephone line as multifrequency digits.

An embodiment of the invention will now be described with reference to the accompanying highly schematic block-diagram.

In the drawing block A includes a line interface 1 via which the terminal is connected to a telephone line, in this case one connected to a public telephone network, although it will be appreciated that the terminal can be used with a PABX. Unit 2 performs the "dialling" functions, which may actually be effected by push-button operation, while unit 3 is an on/off block detector, plus incoming call detection circuitry.

These units can all follow established practice. Thus the overall functions of block A are to match the terminal to the characteristics of the telephone systems to which the terminal is connected, to allow of "dialling" and to recognise when there is a call incoming to the terminal.

Block B includes a digital to MF converter 4, an MF to digital converter 5 and a speech synthesizer 6.

Thus its functions are to modulate and demodulate digital and multifrequency signals with an option for synthetic speech output.

Block C is an interface between the terminal and a microprocessor or other digital equipment, such as modems or other digital terminals.

Block D is in the control equipment for the terminal, and responds to information passing to and from the interface C while that information is in a digital form. It also has an input from unit 3 of block A, so that it monitors the terminal's on/off hook and calling states. As shown by the broken lines it exercises its controlling functions on units A, B and E. It can also "output" information in digital form for transmission from the terminal via block C. Preferably this block D would be based on a microcomputer.

The last block to be described, block E, includes an external line switch circuit 7 for the control of the line to the telephone network, and a remote control unit 8 for the control of external equipment such as alarms, lamps, solenoids, etc. This unit 8 can thus perform a wide variety of local control functions in response to incoming calls.

When a call is made to a terminal such as that shown in the drawing, when an incoming call is received it is detected by the call detector part of the unit 3, which causes a signal to this effect to be passex to the control block D. As a result the incoming call indication, if it is directed to the digital equipment connected to the interface C is converted into digital form, in this case in ASCII code which is recognisable by that digital device. In addition, the connection is switched through so that the telephone line is now connected via the line interface 1, the converters 4 and 5, and the interface C to the digital equipment (not shown). This latter is herein assumed to be a computer such as a microcomputer.

The caller now receives an answering signal, which could be in speech synthesized form, from the synthesizer 6, to indicate that the connection to the computer has been established: with the push buttons on his MF keyphone, the remote caller can now signal into the terminal, which translates the MF tone signals into digital form, in this case using ASCII code, for use by the digital equipment. When the latter receives the code, it responds thereto in accordance with its programming.

In some cases the digital equipment now sends back a signal which is recognised by the control block D as a result of which block A is instructed to to release the connection. When the digital equipment has responded to the information which it thus received, it initiates a call to the remote caller in the manner to be described below. This assumes that the digital equipment will "know" from the information which it has received the identity of that remote caller. Alternatively, especially where the response to the received information is rapid, the terminal may hold the connection until such time as the reply message is available, in which case the message would then be sent without having to release and re-establish the connection.

The reply message whether sent immediately or after re-establishing the call, may be in MF form, using unit 4 of block b, or in spoken form using the speech synthesizer 6.

The calling signals as received at the terminal are such as to indicate whether the call is a normal telephone call, or for the digital equipment when operation is as just described, or for the remote control equipment 8. In the case of a normal telephone call, the response by the terminal is simply to give the normal "ringing" indication. For the remote control function, the control block D responds to the incoming call to connect the line to the external line switch 7, so that incoming signals for the remote control functions are routed to unit 8, which sends out signals as appropriate. In a domestic installation, this could be, for instance, the switch-on of the oven. In any case, any reply signals generated by the remote controlled equipment can be sent back via switch means 7 and the line to the remote caller.

Now we consider the origination of a call from the terminal. In the case of a plain telephone call, operation is conventional, so is not described herein.

Call origination, apart from the normal call case, is assumed to be from the digital equipment, in this case a computer This device sends codes to the terminal which are received via the interface C, and are detected by the control b:ock i These codes include the identity of the remote line tc which the information is to be sent. The block D therefore causes the terminal to go off-hook, i.e. to assume its calling condition, and when the exchange replies with a proceed to send signal (usually dial tone). The terminal, under control of the block D, now emits the wanted number in MF form via units 4 and 1. Note that if necessary this number could be sent out in break impulse form, as needed by Strowger exchanges.

When the called line (or extension in the case of a PABX) responds to the calling signal, this response is noted by the control block D, which latter causes the message to be sent, usually by MF tones. However, in some cases it may be desired to send this information in speech synthesized form. In either case, this information reaches the remote line where it causes the actions called for.

The terminal releases, i.e. goes on-hook, when one of a number of conditions arise. One of these is the receipt of a specified ASCII code from the digital equipment, or the receipt of a specified release signal from the remote extension. Another is the lock of a correct response after a defined time, in which case the time out causes the on-hooking. Yet another is the end of an established call.

Where the speech synthesizer 6 is used to send a message such as the computer's output, this message can be repeated until a correct reply is received.

It can be received directly by the remote caller or recorded at the remote extension on a cassette. Such a spoken message can be repeated until an acknowledgement signal is received. Such repeat until acknowledged can also be used for a message sent in MF form.

The terminal can include in its functions operation as a telephone answering machine if this is desired for incoming telephone calls when the terminal is unattended. It can also call up another similar terminal, in which case the terminal shown includes recording means.

Claims

1. A telephone subscriber's terminal which when in use is connected both to a telephone exchange and to a digital device such as a computer, which terminal includes telephone call-making and receiving equipment for making calls to the telephone exchange and for receiving calls therefrom, a telephone interface which when the terminal is in use is between the terminal's equipment and a line to the exchange, a data interface which when the terminal is in use is between the terminal and the digital device such as the computer, and control means whereby the terminal can be used as required as a computer terminal or as a telephone instrument, and whereby intelligence from the computer can be transmitted over the telephone line as multi-frequency digits.

2. A terminal as claimed in claim 1, in which the control means responds to an incoming call for the digital equipment to set up a connection from the incoming line via the telephone interface to conversion means which converts the incoming information into digital form for transmission via the data interface to the digital device.

3. A terminal as claimed in claim 1 or 2, in which when the digital device initiates a call a digital code indicative thereof is received via the data interface by the control means, in which the control means connects the data interface to further conversion means which converts the message into a form suitable for transmission overtelephone lines, and in which the control means causes a call to be set up to the appropriate remote line under control of information received from the digital device.

4. Atelephone subscriber's terminal, substantially as described with reference to the accompanying drawing.