Automatic data/voice sending/receiving mode switching device

• US 4,873,715 A
• Filed: 06/08/1987
• Issued: 10/10/1989
• Est. Priority Date: 06/10/1986
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shibata, Yoji
• Primary Examiner(s): Brigance, Gerald
• Assistant Examiner(s): HJERPE, RICHARD A
• Application Number:
  US07/059,514
• Time in Patent Office: 855 Days
• Field of Search: 379/93, 379/94, 379/96, 379/98, 370/58, 370/67, 370/110.1
• US Class Current: 379/93.09
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: Y10S 379/902 Auto-switch for an incoming voice data, or fax telephone call, e.g. comp/fax/tel

Abstract

A terminal device sends/receivers data and voice signals through a low speed circuit to/from another device, while switching automatically data and voice signals. The terminal device comprises a data sender/receiver, a voice sender/receiver, a modulator/demodulator, and an automatic mode switch. The automatic mode switch includes a circuit disposed beteen the data sender/receiver and the modulator/demodulator for detecting special data such as flags from received data coming from the modulator/demodulator, a circuit for making a logical product of the output of this detecting circuit and a detection signal of the received carrier and means for separating the voice sender/receiver from the circuit and transmitting a sending request for data sending/receiving use. Further switching over from the voice sending/receiving mode to the data sending/receiving mode is effected by key operations, etc.

Claims

1. A terminal device which sends/receives data and voice signals through a low speed circuit to/from another device, comprising:

data sending/receiving means which sends/receives digital data;

modulation/demodulation means which modulates/demodulates digital data from/to said data sending/receiving means in order to make said digital data conform to said low speed circuit;

voice sending/receiving means which sends/receives voice signals through said low speed circuit; and

voice/data switching means connected between said data sending/receiving means and said modulation/demodulation means for switching between data and voice modes wherein said data mode sends/receives data to/from said other device and said voice mode sends/receives voice to/from said other device;

said voice/data switching means including

detecting means for detecting a received carrier from said other device through said modulation/demodulation means,

means for interrupting said data mode upon detection of an interruption of said received carrier and starting said voice mode, and for connecting said voice sending/receiving means to said low speed circuit,

detecting means for detecting special data from said other terminal device through said modulation/demodulation means,

means for outputting a logical product of an output from said special data detecting means and an output from said received carrier detecting means, said logical product output being connected to said modulation/demodulation means, and

means for setting said data mode according to said logical product output from said logical product means and for disconnecting said voice sending/receiving means from said low speed circuit.

2. A terminal device according to claim 1, wherein said special data detecting means in said voice/data switching means includes a flag synchronization detecting circuit.

3. A terminal device according to claim 1, wherein said voice/data switching means recognizes when a voice sent/received to/from said voice sending/receiving means or data sent/received to/from said data sending/receiving means is terminated or interrupted.

4. A terminal device according to claim 3, wherein said voice/data switching means further comprises:

means for detecting when said data mode is terminated by receipt of a voice actuating signal sent from said voice sending/receiving means; and

means for interrupting issuance of a sending request to said modulation/demodulation means and for interrupting sending of a sending carrier.

5. A terminal device according to claim 3, wherein said voice/data switching means further comprises:

means for delaying data to be sent, until it becomes possible for said other terminal device to pull-in the carrier sufficiently and to receive data, when voice reception is interrupted and data is sent from said data sending/receiving means.

6. A terminal device according to claim 1, wherein said voice sending/receiving means comprises:

means for delaying a received voice from a time when said voice/data switching means begins receiving said received carrier to a time when said voice sending/receiving means is disconnected from said low speed circuit.

7. A terminal device according to claim 1, wherein said voice/data switching means further comprises:

a first flipflop for setting a voice sending mode of said voice mode;

a second flipflop for setting a voice receiving mode of said voice mode;

a third flipflop for setting said data mode;

means for putting said first and second flipflops in a set state and at the same time putting said third flipflop in a reset state based on a voice sending request from said terminal device;

means for putting said first and second flipflops in a set state and at the same time putting said third flipflop in said set state based on detection of a carrier interruption from said other terminal device; and

means for putting said first and second flipflops in a reset state and at the same time putting said third flipflop in a set state based on receipt of a voice sending termination signal from said terminal device or based on a logical product signal of an output of a detecting means for detecting data sent by said other terminal device and said received carrier.

8. A terminal device according to claim 7, wherein said voice/data switching means includes:

first delaying means for delaying a set input to said first flipflop by a first period of time;

second delaying means for delaying a set input to said second flipflop by a second period of time; and

third delaying means for delaying a set input to said third flipflop by a third period of time.

9. A terminal device according to claim 1, wherein said voice/data switching means uses a sending data line, a received data line, a received carrier detection line and a data sending request line among interface connection lines disposed between said data sending/receiving means and said modulation/demodulation means.

10. A terminal device according to claim 1, wherein said data sending/receiving means includes a personal computer having an RS. 232-C interface.

11. A terminal device according to claim 1, wherein said voice sending/receiving means includes a relay contact actuated by a relay driving and control signal from said voice/data switching means in order to perform the disconnection of said voice sending/receiving means from said low speed circuit.

12. A terminal device according to claim 1 wherein said special data detecting means in said voice/data switching means includes a character data detecting circuit for detecting predetermined particular character data sent in stepping synchronization.

13. A terminal device according to claim 1, wherein said special data detecting means in said voice/data switching means includes a SYN synchronization detecting circuit.

14. A terminal device according to claim 1, wherein said voice/data switching means includes sending means for sending said special data by deleting a whole or a part thereof to said data sending/receiving means after detecting said special data.

15. A terminal device according to claim 1, wherein said voice/data switching means further comprises:

means for detecting when said voice mode is terminated or interrupted by detecting data sent from said data sending/receiving means,

means for issuing a sending request to said modulation/demodulation means, and

means for issuing said special data when said termination or interruption detecting means detects termination or interruption of said voice mode.

16. A terminal device according to claim 1, wherein said voice/data switching means further comprises:

means for detecting when said voice mode is terminated by receipt of a voice termination signal sent from said data sending/receiving means,

means for issuing a sending request to said modulation/demodulation means, and

means for issuing the special data when said termination detecting means detects termination of said voice mode.