GB2173613A - Computer interface - Google Patents

Abstract

To enable two computers at opposite ends of a telephone line to work in parallel and under control of both ends an interface unit (4) is provided. This unit, which is itself microprocessor controlled can be operated in a "My input" condition in which the computer is locally controlled, or in a "Both inputs" condition. In the "Both inputs" condition, the data inputs (1,2) are coupled via buffers (8,9) and multiplexers (12,13) to the local computer (3), and also via a multiplexer (10) and a link control device (11) to a link to the other computer. In addition, data from the other computer can arrive via the link control device (11) from which it passes to the computer (3) via a demultiplexer (14) and the multiplexers (12,13). Thus in the "Both inputs" condition the users can collaborate on documents, etc. generation, with their computers each working under dual control. <IMAGE>

Description

SPECIFICATION Computer interface This invention relates to an interface unit for use with a computer to enable that computer and another computer to be operated in parallel with each other.

According to the invention, there is provided an interface unit for use in enabling two computers to operate in parallel, wherein each said computer has its own local manual data input, and wherein the said interface unit when in use is associated with one of said computers and includes (a) an output data link for communication with an interface unit associated with the other computer, (b) control means associated with the local data input via which data from the input is passed to the computer.

(c) a connection from the local data input to link control means associated with the output data link to the other computer's interface unit via which data from the local input device may be sent to the other computer's interface unit, and (d) a connection from control means for the link to the control means for the local data input via which data from the remote computer received via the link control means can be applied to the local computer, the arrangement being such that, via the interface unit the local computer can be controlled by the local data input or the remote computer's data input, and that data for the control of the remote computer can be sent to the remote interface unit from the local data input via the said interface unit's link control means and the data link.

The interface unit is used in association with a computer, such as a personal computer, connected to a telephone line. In such case the other computer is remotely-located at or near another telephone subscriber's instrument, the remote computer having a similar interface unit. Then by proper co-ordination between the two subscribers, the two computers are each controllable from either subscriber's set, in each case via the interface units and the data link. The data link in this case is a telephone line, switched via a PABX or a public exchange, or both. It may, and in fact usually would, be a line additional to that used for the normal telephone speech connection.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which Figure 1 and 2 are highly schematic representations of the interface unit in its two operating conditions.

The use of the interface units, associated with the two computers, assumes that the computers are of the same type or are fully compatible with each other. Also the software in use in the co-operating computer should be identical. This enables the results of computations and other data handling operations by both users to be effected on both computers' read-out devices, usually VDUs.

The interface unit is a "black box" which is located between the keyboard 1, Figure 1 and the mouse 2, of a personal computer 3, such as an IBM PC. It has a switch on top of the box which is settable to two position, "My inputs" and "Both inputs". Figure 1 shows the interface unit in the "My input" condition, and Figure 2 shows it in the "Both inputs" condition.

When in the "My input" condition, Figure 1, the keyboard 1 is coupled via the interface unit 4 to the keyboard port of the computer 3, while the mouse 2 is coupled via the interface unit 4 to the computer's mouse port. The computer's asynchronous port is then coupled via the interface unit 4 to a data line 5 via which the computer can transmit or receive data. This data link would normally be connectable to a remote device of some kind via a modem. In this condition, normal computer operation occurs, under control of the local keyboard 1 and mouse 2.

We now consider the operation in the "Both inputs" condition, Figure 2, which shows schematically the portions of the interface unit which are in use in this condition. The "straight-through" connections shown in Figure 1 do not appear in this figure.

In this condition the inputs from the keyboard 1 and mouse 2 are connected to respective buffers 8 and 9. Whichever input is active has its data characters or bytes modified to permit error checking, whereafter the resulting bytes are sent on the data line/modem port via a multiplexer 10 and link control device 11. When the interface unit 4 receives an indication from the remote computer's interface unit that it is ready, it closes the switches shown connected to the buffers, via the connection marked RECEIVE ACKNOWLEDGE. The receipt of this ACKNOWLEDGE causes the transmitted characters to be passed to the local computer 3 via one or other of its inputs (keyboard or mouse) via the appropriate one of a pair of multiplexers 12 and 13.Data sent from the remote computer arrives over the data link, from which it passes via the link control device 11 to a demultiplexer 14, which passes it to the appropriate one of the multiplexers 12 and 13. Operation is fully duplex, with characters from the remote interface unit being passed to the local computer if checked and found correct.

The link control device 11 may include, or be, microprocesssor controlled.

We now consider the use of such an interface unit, in conjunction with the interface unit at a remote port. If two people at different locations wish to create a document one calls the other by telephone, and they agree to load the same software package into their computers, which is done with the control switch in the "My inputs"position. They establish verbally that they have the same selection menu displayed on their VDUs and then link the keyboards and mice via the data link by setting their switches to "Both inputs". As already indicated these operations cause another connection to be set up through the switching network so that while the "computing" operations are in progress, the speech connection can be used.

Both inputs, keyboards and mice, are now effec tively in parallel and connected to both computers, so both users can look at and modify data, charts, etc. common to both computers. If the data is not common to both computers it can be transferred as a file over the data link, by returning the switch to "My inputs", using existing software.

If they wish to draw and discuss sketches, a software packet such as "PC paint" is loaded, the starting screen and brush aligned by verbal agreement, and then the users' mice connected by the data link. The interface unit can handle mouse/keyboard switching automatically.

Note that if the computer's "async" port is equipped to handle auto-answer, and users agree on the computers' software station when not in use, it is possible to send mail to an unattended machine. In this case care is needed to leave valuable files write protected.

Although the invention has been described as applied to a telephone exchange system it will be appreciated that it is also usable where the subscribers' lines, or nodes to use a fashionabe term, are interconnected via a local area network. In fact this latter may prove to be an equally important exploitation of the invention.

The implementation of the invention described above in largely hardware oriented. In some cases part at least of the hardware may be replaced by software in the private computer or in an addi tonal dedicated computer.

Claims (6)

1. An interface unit for use in enabling two computers to operate in parallel, wherein each said computer has its own local manual data input, and wherein the said interface unit when in use is associated with one of said computers and includes: (a) an output data link for communication with an interface unit associated with the other computer, (b) control means associated with the local data input via which data from the input is passed to the computer.

(c) a connection from the local data input to link control means associated with the output data link to the other computer's interface unit via which data from the local input device may be sent to the other computer's interface unit, and (d) a connection from control means for the link to the control means for the local data input via which data from the remote computer received via the link control means can be applied to the local computer, the arrangement being such that, via the interface unit the local computer can be controlled by the local data input or the remote computer's data input, and that data for the control of the remote computer can be sent to the remote interface unit from the local data input via the said interface unit's link control means and the data link.

2. An interface unit as claimed in claim 1, wherein there are two or more inputs to the local computer each having its own control means, whereupon the two inputs are connected to the link control means via a multiplexer, and wherein the link control means is connected via a demultiplexer to control means for the computer inputs.

3. An interface unit as claimed in claim 2, wherein each input to the interface unit is connected to a buffer in which the data being input for possible transmission over the data link is suitably formatted for such transmission.

4. An interface unit, for use in association with a computer, which unit when in use is coupled to the said computer, to a telecommunication system so as to have access to a remote computer when the unit is in use, and to local manual data inputs, wherein when the unit is in use it is operable in two conditions, the first of which the local manual inputs are connected directly to the said computer, wherein in the second of said conditions (a) the local data inputs are connected to the local computer via control means per local data input, (b) the local data inputs are conriected via a multiplexer and link control means to the telephone line to a remote computer, (c) the link control means is connected via a demultiplexer to the said control means, wherein in operation when a call has been set up via a line to a subscriber with said remote computer both the local computer and the remote computer are effectively in parallel and are both controllable from either or both computers'manual data inputs.

5. An interface unit substantially as described with reference to the accompanying drawing.

New claim filed on 27/11/85 Superseded claims

6. An interface unit, for use in association with a digital computer, which unit is separate from such computer but is coupled to the data inputs thereof when in use, wherein when the interface unit is in use a data link included therein is coupled via a telecommunications channel to a similar interface unit which is itself coupled to another, remote, computer, wherein the interface unit includes control means associated with its own data input and adapted to couple data from that data input to the data input or inputs of the computer with which it is associated or to the said data link for transmission to such other interface unit, which control means can also respond to data from the local computer to apply that data to the data link for transmission to the said remote interface unit, and further control means associated with the data link and responsive to data received from a said remote interface unit to route data therefrom to the local computer, and wherein the arrangement is such that the interface unit enables the local computer to be controlled via that interface unit's data input or inputs and/or from a said remote interface unit via a said transmission channel and the local interface unit's own data link.