FR2565747A1 - Interface between a home microcomputer and a subscriber telephone line - Google Patents

Abstract

The invention relates to a device capable of direct connection to the buses (addresses, data, control) of a microcomputer, on the one hand, and to a telephone line on the other, permitting either data transmissions by modulation/demodulation or automatic use of the line for domestic purposes. This device 11 consists of a circuit 12 comprising means for coupling with the line, a circuit 13 permitting direct connection to the buses of the microcomputer 10, as well as one or more functional circuits 14, all these circuits exchanging signals via an internal electric bus 15. The invention applies in particular to home microcomputing.

Description

 The present invention relates to a device for connecting a home microcomputer to a subscriber telephone line.

 Up to now, the devices fulfilling this function and likely to be used in home microcomputers, required formatting of the signals exchanged, (most often in the opinion CCITT V24) and therefore the intervention of an additional external device, uncommon on home computers. In addition, these devices were mostly limited to simple data transmission (modulator-demodulator).

 The device according to the invention allows a significant improvement with respect to this state, in that it can be directly to the address, data and control buses of the microcomputer concerned, and that in addition to the transm. With the help of appropriate devices, the automatic dialing of telephone numbers, the opening and closing of the telephone line and the detection of calls.

The device according to the invention is composed of three parts:
- The first is an electronic circuit comprising:
. a power supply
. an opening device closing the telephone line
. a device for isolating the telephone line
a call detector device
. a fifty-line electric bus supplying connectors to which the two other parts of the apparatus are plugged.

 . a display device for displaying the logic state of certain signals of this bus, all these elements being dipnsés on a single printed circuit.

 - The second is an electronic circuit for the direct connection of the micro-computer ai device, and comprising on the one hand a printed circuit plugging on one of the previously described connectors, and on the other hand a cable connecting this circuit board to a connector plugging on the microcomputer itself.

 - The third consists of one or more electronic circuits, according to the configuration chosen by the user, arranged on one or more printed circuits, pluggable on the connectors of the circuit of the first part.

These circuits fulfill either data conversion functions (demodulation modulation) or various functions, such as telephone answering machine, programmable clock, electrical power control for devices external to the user's micro-computer installation, etc.
These functions, in combination with the circuit devices of the first part, open the field to domestic applications, such as automatic telephone call, remote control of electrical equipment etc ...

 The electronic circuits making up the three parts of the device exchange logic or analog signals via the bus already mentioned.

The following detailed description is based on the attached drawings which represent
General block diagram of the device according to the invention
(Fig. 1)
the synoptic diagram of the circuit of the first part
(Fig 2)
The block diagram of the circuit of the second part
(Fig. 3)
. the synoptic diagram of a circuit of the third part
(Fig. 4)
The device (11) is connected to the microcomputer (10) by a cable (A) and to the telephone line by two wires (B) and (C). The circuit of the second part (13) and the circuit or circuits of the third part (14) are connected to each other and to the circuit of the first part (12) by the bus (15).

 The circuit (12) comprises a power supply (21) supplying from a mains voltage 220 V, + 5V and - 5V voltages, relative to the electrical ground of the device. The + 5V is connected to the bus wires B1 and B50, the - 5V to the BS wire, the ground to the B2, B3 and B49 wires. This mass is used by all the logic circuits of the device. The mass of the analog circuits is connected to the wire B4. The two masses are united in one point. A display device (25) with light emitting diodes is also provided. It makes it possible to visualize the logical state of the signals of certain wires.

 The wires (B) and (C) of the telephone line are connected to the wires B8 and B10, and feed a call detector (24) (connected to the wire B20) and an adaptation and isolation device ( 23) to a transformer, via a line breaking device (22) connected to the wire B11. The secondary of the device (23) is connected to the wire B7.

 The circuit (13) is connected by the cable (A) to the microcomputer (10), which cable extends the address, data and control buses of the latter.

 The address bus attacks an address decoding device (31) that operates itself, depending on the address, either an asynchronous communications interface adapter device (32) or a peripheral interface adapter device. (33). The device (31) depends on the addresses chosen to operate the device from the microcomputer (10) and therefore varies, depending on the type of microcomputer used. The device (32) is further connected to the bus wires B13 to B19, the device (33) to the wires B29 to B48. These wires all convey logic signals.

 A type circuit (14) comprises a decoding device (41) connected to the wires B41 to B43, for activating or deactivating this circuit.

 If the circuit is of the modulator-demodulator type, it also comprises a modulation-demodulation-filtering device (42) activated by (41), connected on the one hand to the wire B7 (and consequently to the telephone line via the devices ( 22) and (23)), on the other hand to certain logic control wires among the wires B11 to B48 via a 3-state buffer (43) which is also activated by (41).

 In other cases (answering machine, programmable clock, etc.) the circuit (14) comprises a device (42) activated by (41) and connected via a buffer (43) to the wires B7 to B48 , or even directly outside (tape recorder, in the case of an answering machine) through appropriate connections.

The description of the bus wires, as well as the direction of transfer of the signals carried is given by the following table (page 4).

<tb><SEP> Thread <SEP> Function <SEP> Direction <SEP> of <SEP> Transfer <SEP> of <SEP> Signals
<tb> B1 <SEP> + <SEP> 5 <SEP> Volts <SEP> ~~~~~
<tb> B2 <SEP> Mass <SEP> ~~~~~
<tb> B3 <SEP> Mass <SEP> ~~~~~
<tb> B4 <SEP> Mass <SEP> analog <SEP> ~~~~~
<tb> B5 <SEP> - <SEP> - <SEP> 5 <SEP> Volts <SEP> ~~~~~
<tb> B6 <SEP> unused <SEP> ~~~~~~
<tb> B7 <SEP> Secondary <SEP> of <SEP> (23) <SEP> Bidirectional <SEP> of <SEP> (12) <SEP> to <SEP> (14)
<tb> B8 <SEP> Line <SEP> Telephone <SEP> (B) <SEP> same
<tb> B9 <SEP> not used <SEP> ~~~~~~
<tb> B10 <SEP><SEP> Telephone Line <SEP> (C) <SEP> bidirectional <SEP> from <SEP> (12) <SEP> to <SEP> (14)
<tb> B11 <SEP> - <SEP> Command <SEP> closing <SEP> of <SEP> line <SEP> (14) <SEP> - <SEP> (12)
<tb> B12 <SEP> unused <SEP> ~~~~~~~
<tb> B13- <SEP> Ready <SEP> to <SEP> Transmit <SEP> (14) <SEP> ~ <SEP> (13)
<tb> B14 <SEP><SEP> Carrier <SEP> Detection (14) <SEP> ~ <SEP> (13)
<tb> B15 <SEP> Received <SEP> Data <SEP> (14) <SEP> (13)
<tb> B16 <SEP> Clock <SEP> Receive <SEP> (14) <SEP> ~ <SEP> (13)
<tb> B17 <SEP> Clock <SEP> broadcast <SEP> (14) <SEP> ~ <SEP> (13)
<tb> B18 <SEP> Order <SEP> to issue <SEP> (13) <SEP> ~ <SEP> (14)
<tb> B19 <SEP> Data <SEP> Issued <SEP> (13) <SEP> ~ <SEP> (14)
<tb> B20 <SEP><SEP> Call Detection <SEP> (12) <SEP> ~ <SEP> (14)
<tb> B21 <SEP><SEP> indicator of <SEP> test <SEP> (14) <SEP> (12)
<tb> B22 <SEP> to <SEP> B28 <SEP> not used <SEP> ~~~~~
<tb> B29, <SEP> B30 <SEP> 1 <SEP><SEP> Port <SEP> 1 <SEP> of <SEP> (33) <SEP> bidirectional <SEP> of <SEP> (13) <SEP> to <SEP> (14) <SEP> a <SEP> priori
<tb><SEP> pl
<tb> and <SEP> B32 <SEP><SEP> Port <SEP> 2 <SEP> of <SEP> B41 <SEP> - <SEP> Bidirectional <SEP> of <SEP> (13) <SEP> to <SEP> (14) <SEP> to
<tb> Port <SEP> n0 <SEP> 2 <SEP> from <SEP> (33) <SEP> to <SEP> bidirectional <SEP> from <SEP> (13) <SEP> a <SEP> (14) <SEP> to <SEP> priol
<tb> B49 <SEP> Mass <SEP> o
<tb> B50 <SEP> + <SEP> 5 <SEP> Volts <SEP> ~~~~~~
<Tb>

 The operation of the device will be explained by means of an example, for which it is assumed that only one circuit (14) is used and that this circuit is of the modulator-demodulator type.

 The interface adapter devices (32) and (33) are first initialized by addressing the apparatus such that the address decoding device (31) is activated. During this initialization phase, it is then possible to program the peripheral interface adapter device (33) so that, for example, the signals of the wires B41 to B46 are exchanged in the direction (13) ~ (14). ) and that the signals of the other bus wires connected to (33) are exchanged in the other direction.

 We can now program (33) (always by addressing the device so that (31) is activated) so that the signals present on the wires B41 to B43 activate the device (41) and consequently the device modulation-demodulation-filtering device (42) and the buffer (43).

Thus enabled, the device (42) can exchange with the asynchronous communications interface adapter (32), all the signals necessary for data transmission, in particular those conveyed on the one hand by the wires
B13 to bol9. The device (42) further connects the B20 and B48 wires, thereby detecting a call by appropriate B48 state polling using the peripheral interface adapter (33) and the B11 and B11 wires. B46 on the other hand, which allows to control the closure of the line by an action on the wire 846; always by means of (33).

 All signals relating to the data transmission are accessible in the same way, read or write as appropriate by means of the asynchronous communications interface adapter device (32).

 Any operation on (32) and (33), of course, requires proper addressing to activate the address decoding device (31).

 The device according to the invention thus makes it possible to couple a home microcomputer and a subscriber telephone line without the intervention of any external device for shaping the signals exchanged by direct connection to the data bus. and control of this microcomputer.

Claims (4)

1 - Interface device between a home microcomputer and a  subscriber telephone line characterized in that it comprises a circuit  (12) comprising coupling means (23) with the telephone line,  a circuit (13) allowing the direct connection to the buses (addresses,  data, control) of the microcomputer (10), as well as one or more  circuits (14) performing either data transmission functions,  functions related to automatic use of the telephone line  all these circuits exchanging signals by means of a bus  internal electric (15). 2 - Device according to claim 1 characterized in that it comprises  means for opening and closing the telephone line (22)  and call detection means (24).  (33).  asynchronous (32) and / or peripheral interface adapter device  (31) activating a communications interface adapter device  with the microcomputer, includes an address decoding system  characterized in that the circuit (13) for direct connection  3 - Device according to any one of the preceding claims, 4 - Device according to claims 1 and 3, characterized in that  the functional circuits (14) each comprise a decorative device  (41) allowing their activation or deactivation, the said  device itself being activated by the state of certain lines of the bus  from the peripheral interface adapter (33).