CIRCUIT DEVICE FOR USE WITH A COMPUTER

Abstract: A circuit device for connecting a personal computer (10) to an accessory device such as a cassette recorder (40), the computer being of the type having an audio circuit (12, 14, 18) for generating tones. The circuit device comprises a first jack plug (22) connected to the coil of an alternating current relay (20), and a second jack plug (24) connected to contacts of the relay (20). The first jack plug (22) is adapted to be inserted into a receptacle (16) associated with the audio circuit (12, 14, 18), and the second jack plug (24) is adapted to be inserted into a receptacle of the cassette recorder (40). With the jack plugs (22, 24) inserted into their respective receptacles, an audio frequency electrical signal generated by the audio circuit (12, 14, 18) activates the relay (20) which, in turn, brings about activation of the cassette recorder (40). By virtue of this arrangement, the cassette recorder (40) can be activated at selected times under the control of the computer (10).

Description: CIRCUIT DEVICE FOR USE WITH A COMPUTER Technical Field This invention relates to a circuit device for use with a computer of the type having an audio circuit for generating tones. The invention has particular application to a circuit device for use with a personal computer and with an accessory device, such as a cassette recorder. Background Art In the personal computer art, the software of a computer creates a display upon the CRT screen, and it may be desired to commence operation of an accessory device at a particular time in the course of such display. For example, in learning type environments, it may be desired to augment the visual display with an audio presentation. However, problems may be experienced in synchronizing the audio presentation with the display. Disclosure of the Invention It is an object of the invention to provide a simple and inexpensive circuit device for use with a computer of the type having an audio circuit for generating tones, which circuit device may be used to bring about operation of an accessory device under the control of the computer. It is a further object of the invention to provide a simple and inexpensive circuit device for synchronizing an accessory device to such computer. According to the invention, there is provided a circuit device for use with a computer and an accessory device wherein the computer is of the type having an audio circuit for generating tones, characterized by first conductor means adapted to be coupled to said audio circuit for receiving an audio frequency electrical signal generated by said audio circuit, switch means connected to said first conductor means and responsive to said audio frequency electrical signal for activation thereby, and second conductor means for connecting said switch means to said accessory device for enabling the activation of said accessory device in response to activation of said switch means. It should be understood that by using a circuit device in accordance with the invention a computer may be programmed to activate an accessory device through the generation of audio frequency electrical signals, at selected times and for selected time periods so as to provide a supplemental source of information to the computer user. Brief Description of the Drawings An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:- Fig. 1 is a perspective view partially in phantom outline and partially in cut-away showing the preferred embodiment of a circuit device in accordance with the present invention interfacing with a computer and a cassette recorder; Fig. 2 is a schematic circuit diagram of the circuit device of Fig. 1 and associated parts of the computer and cassette recorder; and Fig. 3 is a schematic diagram illustrating a second application of the circuit device in accordance with the invention. Best Mode for Carrying Out the Invention Referring now to Fig. 1, a personal computer (such as an NCR PC-4) labeled 10 is shown containing a component board 11 on which is mounted a speaker 12 and a driver circuit 14 for translating digital signals into an audio frequency electrical signal of sufficient power to drive speaker 12. A connector 18 receives the output wires from the driver and is used to connect those wires with the input to the speaker 12. A female receptacle (jack) 16 is affixed to the back wall of the cabinet of the personal computer. A cable 15, extending from the receptacle 16, is directed to the connector 18. A jack plug 22 designed to be received by the receptacle 16 is electrically connected by a cable assembly 21 to a relay unit 20. In the preferred embodiment of the invention, the relay is a CLARE model 925A05 type alternating current relay having a set of normally open (NO) contacts 26 (See Fig. 2). The contact outputs from the relay 20 are electrically coupled to a jack plug 24 by means of a cable 23. The plug 24 is adapted to be received by a computer accessory such as a cassette recorder 40. Referring now to Fig. 2, the jack plug 22 is electrically connected across the relay coil 25 of relay 20 by the cable 21. The plug receptacle 16 is wired to connector 18 by the cable 15 so as to electrically disengage the speaker 12 from the driver circuit 14 and to connect the relay coil 25 to the output of the driver circuit 14 when plug 22 is inserted. The relay coil 25 has a 300ohm resistance and a 2.5V pull-in and " when energized by an audio frequency signal from the driver circuit 14 will close the normally open contacts 26, thereby creating a closed circuit sensible at the plug 24 through the conductors of cable 23. In most instances in a cassette recorder, the closing or shorting of the input terminals causes the recorder to be activated. In those instances where a normally closed circuit causes the accessory device to remain in a deactive position and an open circuit is needed to activate the accessory, a relay having the same characteristics as the aforedescribed relay could be used with the exception that the normally open contacts would now be normally closed. If the accessory device is power actuated, a power source could also be inserted in line with cable 23 such that power is applied to the accessory device when contacts 26 close. The relay 20 requires a certain energy content to be applied to coil 25 in order to have the relay close ' the contacts 26. Once close, a lower level of applied energy will maintain the contacts closed. The software used in the personal computer is programmed in a well-known manner to call for an audio tone which has a duration corresponding to the desired length of time that the cassette recorder 40 is to be run. Such call causes the driver circuit 14 to generate an audio frequency electrical signal which has the correct energy content to activate the relay 20 so as to close the contacts 26 and thereby activate the cassette recorder 40. A tone between 700Hz and 15000Hz has been found to be acceptable with the 925A05 type relay. The pulse signal corresponding to the tone and having a pulse width of 20 milliseconds and an amplitude of at least 2.5V will activate the relay. A pulse rest of 50 milliseconds will permit the relay to deactivate. The computer tone thereby enables a synchronized activation of the cassette recorder. Operating in this manner, it is possible to display data on the personal computer's CRT and to simultaneously provide a supplemental voice narration from the cassette recorder. This is particularly advantageous in learning type environments where the CRT may be teaching a visual lesson which is supplemented by the audio. Referring now to Fig. 3, wherein a second application of the invention is shown, the circuit may be used to automatically dial a telephone in response to the computer closing and opening the relay contacts 26 in response to audio frequency signals received by the relay 20. Affixed to a wall 69, is a telephone receptacle jack 70 which receives a standard four conductor telephone type connector 72. The connector 72 is connectable by a cable 74 to a junction box 60. The junction box 60 contains a ferrule 66 which locks the cable 74 and its four conductors to the box. A female jack receptacle 64 is electrically connected in one line of the four conductors of cable 74 in such a manner that normally the fourth conductor remains electrically unbroken between the input connector 72 and an output connector 62. A telephone 55 is connected by means of cable 52 to a standard telephone connector 50 of the four conductor type. Connector 50 mates with connector 62. The assembly shown in Figs. 1 and 2 containing the relay 20, jack plugs 22 and 24 is connectable by plug 24 to the assembly of Fig. 3, i.e. plug 24 is insertable into the jack receptacle 64 and the plug 22 is insertable into the backpanel of the personal computer 10 via receptacle 16. In operation, signals corresponding to the desired telephone number to be dialed can be transmitted from the computer through the relay contacts 26 to the telephone dialing line.

Claims: CLAIMS 1. A circuit device for use with a computer (10) and an accessory device (40; 55) wherein the computer is of the type having an audio circuit (12, 14, 18) for generating tones, characterized by first conductor means (21, 22) adapted to be coupled to said audio circuit for receiving an audio frequency electrical signal generated by said audio circuit, switch means (20) connected to said first conductor means and responsive to said audio frequency electrical signal for activation thereby, and second conductor means (23, 24) for connecting said switch means to said accessory device for enabling the activation of said accessory device in response to activation of said switch means (20). 2. A circuit device according to claim 1, characterized in that said switch means is an alternating current relay (20) having a coil (25) and contacts (26), said coil being connected to said first conductor means (21, 22) and said contacts (26) being arranged to be activated in response to energization of said coil by said audio frequency electrical signal. 3. A circuit device according to either claim 1 or claim 2, characterized in that each of said first and second conductor means (21, 22; 23, 24) includes a respective jack plug (22; 24). 4. The combination of a circuit device according to either claim 1 or claim 2, and said computer (10), characterized in that said first conductor means (21, 22) includes a jack plug (22) adapted to be inserted into a receptacle (16) associated with said audio circuit (12, 14, 18) of said computer (10), said audio circuit including a speaker (12) and a driver circuit (14) therefor, insertion of said jack plug into said receptacle serving to disconnect said driver circuit from said speaker and to connect said driver circuit to said switch means (20). 5. The combination of a circuit device according to either claim 1 or claim 2, said computer (10) and a cassette recorder (40), characterized in that said first conductor means (21, 22) includes a first jack plug (22) adapted to be inserted into a first receptacle (16) associated with said audio circuit (12, 14, 18) of said computer, said audio circuit including a speaker (12) and a driver circuit (14) therefor, and said second conductor means (23, 24) includes a second jack plug (24) adapted to be inserted into a second receptacle (64) forming part of said cassette recorder (40), insertion of said first jack plug into said first receptacle serving to disconnect said driver circuit from said speaker and to connect said driver circuit to said switch means (20), and said second receptacle being so constructed that, with said second jack plug inserted therein, activation of said switch means serves to bring about activation of said cassette recorder. 6. The combination of a circuit device according to either claim 1 or claim 2, said computer (10) and a telephone (55) to be dialed by said computer, characterized in that said first conductor means (21, 22) includes a first jack plug (22) adapted to be inserted into a first receptacle (16) associated with said audio circuit (12, 14, 18) of said computer, said audio circuit including a speaker (12) and a driver circuit (14) therefor, and said second conductor means (23, 24) includes a second jack plug (24) adapted to be inserted into a second receptacle (64) forming part of connection means (60) convertable to said telephone, insertion of said first jack plug into said first receptacle serving to disconnect said driver circuit from said speaker and to connect said driver circuit to said switch means (20), and said connection means (60) being so constructed that, with said second jack plug inserted in said second receptacle (64), appropriate activation and deactivation of said switch means serves to bring about dialing of said telephone.

Inventors: SMALL JAMES ROBERT, SMALL, JAMES, ROBERT
Applicants: NCR CO, NCR CORPORATION
Application year: 1986
Main classification: G06F3
IPC codes: G06F3, G06F13, G11B15, H04M1