Data circuit-terminating equipment with power source device

• US 5,181,240 A
• Filed: 05/08/1991
• Issued: 01/19/1993
• Est. Priority Date: 11/04/1988
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kuroda, Takashi, Ikeda, Takeshi, Sakuragi, Satoshi
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Chan, Wing F.
• Application Number:
  US07/696,935
• Time in Patent Office: 622 Days
• Field of Search: 379/98, 379/93, 379/96, 379/97, 379/100, 379/413, 375/5, 375/8
• US Class Current: 379/93.36
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 19/08 with current supply sources at the substations generating ringing current H04M19/04

Abstract

A data circuit-terminating equipment with a power source device attached thereto comprising a data circuit-terminating device such as a modem system including a power source device for supplying a power extracted from a telephone circuit to the data circuit-terminating device.

Claims

1. A data circuit-termination apparatus, comprising:

a modem system connected to a telephone circuit and a data terminal equipment, said modem system at least for demodulating a circuit signal which is input from said telephone circuit and supplying the demodulated signal to said data terminal equipment, said modem system comprising;

a modulation and demodulation circuit for modulating a signal supplied from said data terminal equipment and demodulating a circuit signal supplied from said telephone circuit;

a two-wire four-wire circuit connected to said modulation and demodulation circuit;

a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook and supplying said power to said modulation and demodulation circuit; and

a net control circuit for supplying power from the circuit signals in the offhook current which flows on the telephone circuit to said power source device and supplying a signal current from the offhook current to said two-wire four-wire circuit, said net control circuit including a constant current circuit and a smoothing circuit for smoothing said offhook current output from said constant-current circuit, said net control circuit including a circuit for supplying said offhook current to said constant current circuit, said supplying circuit being activated upon detection of an offhook state.

2. The data circuit-termination apparatus according to claim 1, wherein said net control circuit includes a shunt regulator for suppressing the excess of said offhook current output from said constant-current circuit.

3. The data circuit-termination apparatus according to claim 1, wherein said net control circuit includes a transistor circuit for supplying said offhook current to said constant current circuit, said transistor circuit being turned on when a first light receiving element detects the offhook state.

5. The data circuit-termination apparatus according to claim 1, wherein said power source device includes a power converter circuit for converting said offhook current to said power.

6. The data circuit-termination apparatus according to claim 5, wherein said power source device includes a battery for supplying a battery power to said modulation and demodulation circuit only at the time of onhook.

7. The data circuit-termination apparatus according to claim 5, wherein said power converter circuit includes a DC-DC converter for converting said offhook current to a DC current having a different value.

8. The data circuit-termination apparatus according to claim 7, wherein said power converter outputs two kinds of currents for supply to said modulation and demodulation circuit and said two-wire four-wire circuit, respectively.

9. The data circuit-termination apparatus according to claim 7, wherein said power converter circuit is a self-excited converter.

10. The data circuit-termination apparatus according to claim 7, wherein said two-wire four-wire circuit includes:

a light receiving element for receiving a signal in the form of a light transmitted from said modulation and demodulation circuit; and

a light emitting element for emitting a signal in the form of light to said modulation and demodulation circuit.

4. The data circuit-termination apparatus according to claim wherein said net control circuit includes a means for controlling the connection between said modulation and demodulation circuit and said telephone circuit.

11. A modem system which is connected to a telephone circuit and a data terminal equipment said modem system at least for demodulating a circuit signal which is input from said telephone circuit and supplying the demodulated signal to said data terminal equipment, said modem system comprising:

a modulation and demodulation circuit for modulating a signal supplied from said data terminal equipment and demodulating a circuit signal supplied from said telephone circuit;

a two-wire four-wire circuit connected to said modulation and demodulation circuit;

a power source device for separating a power from an offhook current which flows on said telephone circuit at the time of offhook and supplying said power to said modulation and demodulation circuit; and

a net control circuit for supplying power from the circuit signals in the offhook current which flows on the telephone circuit to said power source device and supplying a signal current from the offhook current to said two-wire four-wire circuit, said net control circuit including a lowpass filter circuit for passing a direct current portion in said offhook current output and coupling an input side of said power source device.

12. The modem system according to claim 11, wherein said net control circuit includes a shunt regulator for suppressing the excess of said offhook current output from said constant current circuit.

13. The modem system according to claim 11, wherein said net control circuit includes a constant current circuit for obtaining a constant current from said offhook current and means for preventing said direct current portion from flowing to said two-wire four-wire circuit.

14. The modem system according to claim 13, wherein said net control circuit includes a transistor circuit for supplying said offhook current to said constant current circuit and being turned on when a first light receiving element detects the offhook state.

15. The modem system according to claim 11, wherein said net control circuit includes a means for controlling the connection between said modulation and demodulation circuit and said telephone circuit.

16. The modem system according to claim 11, wherein said power source device includes a power converter circuit for converting said offhook current to said power.

17. The modem system according to claim 16, wherein said power source device includes a battery for supplying a battery power to said modulation and demodulation circuit only at the time of onhook.

18. The modem system according to claim 16, wherein said power converter circuit includes a DC-DC converter for converting said offhook current to a DC current having a different value.

19. The modem system according to claim 18, wherein said power converter outputs two kinds of currents for supply to said modulation and demodulation circuit and said two-wire four-wire circuit, respectively.

20. A data circuit-termination apparatus, comprising:

a data circuit-terminating device comprising a modem system which is connected to a telephone circuit and a data terminal equipment at least for demodulating a circuit signal which is input from said telephone circuit and supplying the demodulated signal to said data terminal equipment; and

a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook and for supplying said power to said data circuit-terminating device;

said data circuit-terminating device including a net control circuit for separating power from the circuit signals in the offhook current which flows on the telephone circuit, and said power being supplied to said power source device;

said power source device including a power converter circuit for converting said offhook current to said power and a battery for supplying a battery power to said data circuit-terminating device only at the time of onhook.

21. The data circuit-termination apparatus according to claim 20, wherein said data circuit-terminating device includes:

a modulation and demodulation circuit for modulating a signal supplied from said data terminal equipment and demodulating a circuit signal supplied from said telephone circuit;

a two-wire four-wire circuit connected to said modulation and demodulation circuit;

a net control circuit for supplying power from the circuit signals in the offhook current which flows on the telephone circuit to said power source device and supplying a signal current from the offhook current to said two-wire four-wire circuit; and

said net control circuit including a constant current circuit for keeping said offhook current in the form of a constant current and a smoothing circuit for smoothing said offhook current output from said constant current circuit.

22. A data circuit-termination apparatus comprising:

a data circuit-terminating device comprising;

a modulation and demodulation circuit for modulating a signal supplied from a data terminal equipment and demodulating a circuit signal supplied from a telephone circuit;

a net control circuit for controlling the connection between said modulation and demodulation circuit and said telephone circuit;

a two-wire four-wire circuit connected to said modulation and demodulation circuit and divided into a transmitting circuit and a receiving circuit;

said net control circuit including a first light receiving element for detecting the offhook state, a transistor circuit for turning on when said first light receiving element detects the offhook state, a constant current circuit for keeping an offhook current in the form of a constant current, a shunt regulator for suppressing the excess of said offhook current output from said constant current circuit and a smoothing circuit for smoothing said offhook current output from said constant current circuit, said two-wire four-wire circuit including a second light receiving element for receiving a signal in the form of light transmitted from said modulation and demodulation circuit, and a light emitting element for emitting a signal in the form of light to said modulation and demodulation circuit;

said data circuit-terminating device being a modem system which is connected to said telephone circuit and said data terminal equipment so as to demodulate said circuit signal input from said telephone circuit and output said signal to said data terminal equipment, and modulate a signal input from said data terminal equipment and supply said signal to said telephone circuit; and

a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook and supplying said power to said modulation and demodulation circuit.

23. The data circuit-termination apparatus according to claim 22, wherein said power source device includes a power converter circuit for converting said offhook current to said power.

24. The data circuit-termination apparatus according to claim 23, wherein said power source device includes a battery for supplying a battery power to said data circuit-terminating device only at the time of onhook.

25. The data circuit-termination apparatus according to claim 23, wherein said power converter circuit includes a DC-DC converter for converting said offhook current to a DC current having a different value.

26. The data circuit-termination apparatus according to claim 25, wherein said DC-DC converter outputs two kinds of currents for supply to said modulation and demodulation circuit and said two-wire four-wire circuit, respectively.

27. The data circuit-termination apparatus according to claim 25, wherein said DC-DC converter is a self-excited converter.

28. A data circuit-termination apparatus comprising:

a data circuit-terminating device comprising a modem system which is connected to a telephone circuit and a data terminal equipment, said data circuit-terminating device at least for demodulating a circuit signal which is input from said telephone circuit and for supplying the demodulated signal to said data terminal equipment;

a power source device for extracting a power from an offhook current which flows on said telephone circuit at the time of offhook and for supplying said power to said data circuit-terminating device, said power source device including a battery for supplying a battery power to said data circuit-terminating equipment only at the time of on hook.