JP2002044239A - Telephone set control circuit, telephone set control method and terminal adapter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable reduce a consumption current by automatically restraining a current with a telephone set control circuit when a telephone set whose con sumption current during calling is small is used. SOLUTION: A -48V power supplying/ring signal transmitting circuit 11 has interface with a telephone set 20 and supplies a prescribed constant current by superposing it on a ring signal. A voltage detecting circuit 15 monitors and detects a voltage at a telephone set terminal which is supplied from the circuit 11. A control circuit 16 compares a value detected by the voltage detecting circuit 15 with a previously determined threshold. When the detected value is lower than the threshold, the circuit 16 judges that a load of a ring circuit included in the telephone set 20 to be connected is light and reduces a constant current supplied from the circuit 11. When the detected value is higher than the threshold, the circuit 16 decides that the load of the ring circuit is heavy and maintains a constant current supplied from the circuit 11 at a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a telephone control circuit for a telephone interface, a telephone control method, and a terminal adapter.

[0002]

2. Description of the Related Art Conventionally, telephone control circuits, for example, ISD
It is used for the telephone interface of the N-line terminal adapter. Such a telephone control circuit generally has a function equivalent to a telephone line in order to operate the telephone, and supplies a voltage and a current to the telephone. As a function among them, the telephone control circuit sends a ring signal equivalent to, for example, 75 Vrms as a calling signal to ring the telephone when there is an incoming call.

On the other hand, recent terminal adapters operate at the time of a power failure and are therefore compatible with batteries. Therefore, transmission of a ring signal consumes a large amount of current, which greatly affects the battery life. In recent telephones, many telephones do not require a large amount of ring current because the load is small due to the digitization of the ring circuit.

[0004]

As the telephone control circuit used in the above-mentioned conventional terminal adapter, it is necessary to operate all the ring circuits of the telephone including the conventional ring circuit. Has the problem of having to be large.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone control circuit, a telephone control method, and a terminal capable of automatically reducing the current consumption when a telephone having a small current consumption for calling is used. To provide an adapter.

[0006]

SUMMARY OF THE INVENTION A telephone control circuit according to the present invention is a telephone control circuit for interfacing with a telephone and transmitting a ring signal for ringing the telephone. Unit, a voltage detection unit that monitors and detects the voltage at the telephone terminal supplied from the power supply unit, and compares the value detected by the voltage detection unit with a predetermined threshold value, and the detected value is equal to the threshold value. If the detected value is lower than the threshold value, the load of the ring circuit built in the connected telephone is determined to be light, and the constant current supplied from the power supply unit is reduced. A control unit that determines that the current is heavy and maintains a constant current supplied from the power supply unit at a predetermined value.

Further, the telephone control circuit of the present invention comprises a constant current circuit for supplying a predetermined constant current from a plurality of types to the telephone, and a ring signal for superimposing the constant current and transmitting a ring signal for ringing the telephone. A power supply / ring signal transmission circuit having a transmission circuit; a communication circuit forming a communication path; a switch circuit for switching between the power supply / ring signal transmission circuit and the communication circuit; and a line connected to the telephone A polarity inversion circuit for inverting the polarity of a voltage, a voltage detection circuit for detecting a voltage at a telephone terminal supplied from the power supply / ring signal transmission circuit, a detection value detected by the voltage detection circuit and a predetermined threshold value. The load of the ring circuit built in the connected telephone is determined, and as a result, when the detected value is lower than the threshold value, it is determined that the load of the ring circuit is light. When the detected value is higher than the threshold value, the constant current supplied from the constant current circuit is determined to be heavy and the constant current supplied from the constant current circuit is maintained at a predetermined value. The constant current circuit is configured to output a current in an arbitrary predetermined step.

A telephone control method according to the present invention is a telephone control method for interfacing with a telephone and controlling transmission of a ringing signal for telephone ringing on which a predetermined constant current is superimposed. In this method, an incoming call is detected and a predetermined ring signal is transmitted to the telephone. Then, the voltage of the telephone terminal is detected, the detected value is compared with a predetermined threshold value, the load of the ring circuit built in the connected telephone is determined, and as a result, the detected value is greater than the threshold value. When the load is low, it is determined that the load of the ring circuit is light,
When the supplied constant current is reduced and the detected value is higher than the threshold value, the load of the ring circuit is determined to be heavy, and the supplied constant current is maintained at a predetermined value. The current is output by any predetermined step.

A terminal adapter according to the present invention is a telephone control circuit for interfacing with a telephone and transmitting a ring signal for ringing a telephone, a power supply for supplying a predetermined constant current superimposed on the ring signal, and the power supply. And a voltage detector for monitoring and detecting the voltage at the telephone terminal supplied from the telephone terminal, and comparing the value detected by the voltage detector with a predetermined threshold value and connecting when the detected value is lower than the threshold value. It is determined that the load of the ring circuit built in the telephone is light, and the constant current supplied from the power supply unit is reduced. When the detected value is higher than the threshold value, the load of the ring circuit is determined to be heavy and the power supply is determined. And a control unit for maintaining a constant current supplied from the unit at a predetermined value. Further, the terminal adapter of the present invention has a constant current circuit for supplying a predetermined constant current from a plurality of types to the telephone, and a ring signal transmission circuit for transmitting the ring signal for superimposing the constant current and ringing the telephone. A power supply / ring signal transmission circuit, a communication circuit forming a communication path, a switch circuit for switching between the power supply / ring signal transmission circuit and the communication circuit, and inverting the polarity of a line connected to the telephone. A polarity inversion circuit, a voltage detection circuit for detecting a voltage at a telephone terminal supplied from the power supply / ring signal transmission circuit, and a voltage detection circuit that compares the detection value detected by the voltage detection circuit with a predetermined threshold and is connected. The load of the ring circuit built in the telephone is determined, and as a result, when the detected value is lower than the threshold value, it is determined that the load of the ring circuit is light, and A control unit that reduces the constant current supplied from the current circuit and determines that the load of the ring circuit is heavy when the detected value is higher than the threshold value, and maintains the constant current supplied from the constant current circuit at a predetermined value; Is used. The constant current circuit is configured to output a current by an arbitrary predetermined step.

According to the present invention, when a ring signal for ringing a telephone is transmitted, the magnitude of the load of a ring circuit built in the connected telephone is detected and determined by detecting the voltage of the terminal of the telephone. When the load is light, the current supplied when the ring signal is transmitted is reduced, and when the load is heavy, the supplied current is maintained at a predetermined value. This makes it possible to save power according to the specifications of the telephone to be connected.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, a telephone control circuit 10 used for a terminal adapter is connected to a telephone 20, and the telephone control circuit 10 supplies a predetermined constant current to the telephone 20 from a plurality of types. -48V having a constant current circuit 17 and a ring signal transmitting circuit 18 for transmitting a ring signal for superimposing a constant current and ringing the telephone 20
Power supply / ring signal transmission circuit 11, communication circuit 12 forming a communication path, -48V power supply / ring signal transmission circuit 1
Switch circuit 1 for switching between communication circuit 1 and communication circuit 12
3, a polarity inversion circuit 14 for inverting the polarity of a line connected to the telephone set 20, a voltage detection circuit 15 for detecting a voltage at the telephone terminal supplied from the -48V power supply / ring signal transmission circuit 11, and a voltage detection circuit. The detected value detected in step 15 is compared with a predetermined threshold value to determine the load of a ring circuit (not shown) built in the telephone to be connected. If the detected value is lower than the threshold value, the ring is determined. It is determined that the load of the circuit is light and the constant current supplied from the constant current circuit 17 is reduced. When the detected value is higher than the threshold value, it is determined that the load of the ring circuit is heavy and the constant current supplied from the constant current circuit 17 is predetermined. And a control circuit 16 for maintaining the value of The constant current circuit 17 is configured to output a current in an arbitrary step predetermined according to an instruction from the control circuit 16.

FIG. 2 is a flowchart showing the flow of processing according to the embodiment of the present invention. The operation will be described below with reference to FIGS.

When the telephone control circuit 10 detects an incoming call (Step 1: abbreviated as S1), the -48V power supply / ring signal transmission circuit 11 transmits a signal in which a ring signal is superimposed on -48V to the telephone set 20 to the telephone 20. (S2). The ring signal is sent to the telephone set 20 via the switch circuit 13 for switching with the communication circuit 12 and the polarity inversion circuit 14. The switch circuit 13 selects one of the -48 V power supply / ring signal transmission circuit 11 and the communication circuit 12 according to a control signal from the control circuit 16 and connects to the telephone 20 via the polarity inversion circuit 14.

The voltage detection circuit 15 detects the voltage at the telephone terminal of the telephone 20 supplied from the -48 V power supply / ring signal transmission circuit 11 (S3), and the control circuit 16 compares the detected value detected by the voltage detection circuit 15 with the detected value. The load is compared with a predetermined threshold value (S4), and the load of a ring circuit (not shown) built in the connected telephone set 20 is determined. As a result, when the detected value is lower than the threshold value, it is determined that the load on the ring circuit is light (S5), and it is determined whether the constant current supplied from the constant current circuit 17 can be reduced (S6). If so, lower the value of the constant current and send (S
7), proceed to the processing of step 3. If the supply current value cannot be reduced in the processing of S6, the supply current value is maintained at a predetermined value (S9).

On the other hand, when the detected value is higher than the threshold value, it is determined that the load on the ring circuit is heavy (S8), and the constant current supplied from the constant current circuit 17 is maintained at a predetermined value (S8).
9). For example, the ring signal has a blunt waveform and a low voltage depending on the load of the telephone 20. This is detected by the voltage detection circuit 15 and a signal is sent to the control circuit 16 based on the threshold value. The control circuit 16 controls the constant current circuit 17 to change the value of the constant current to save power. Therefore, the magnitude of the load at the time of transmitting the ring signal to the telephone 20 is determined by the ring voltage, and when the load is small, the current consumption can be reduced by reducing the supply current of the ring signal.

Next, the operation of the telephone control circuit 10 will be described with reference to the waveform diagrams of the specific examples shown in FIGS. FIG.
FIG. 4 is a diagram showing timing of a ring waveform when a load on a ring circuit of a telephone is light. When the initial values of the ring voltage and the supply current of the ring signal are −180 V / 15 mA and the threshold value is −120 V, the voltage detection circuit 15
Detects a voltage of 120 V or less and sends a signal to the control circuit 16. The control circuit 16 determines that the load on the telephone is light, and instructs the constant current circuit 17 to change the value of the constant current to 10 mA. Even in the case of 10 mA, the ring waveform does not change, and the voltage detection circuit 15 detects -120 V or less, and the control circuit 1
6 again. The control circuit 16 again determines that the load on the telephone is light, and changes the value of the constant current of the constant current circuit 17 to 5 mA. Even in the case of 5 mA, the ring waveform does not change, the voltage detection circuit 15 detects -120 V or less, and sends a signal to the control circuit 16 again, and the control circuit 16 maintains the constant current value of the constant current circuit 17 at 5 mA. I do. In this example, the case where the step of the supply current is 5 mA and the minimum value is 5 mA is shown. Therefore, in the above-described example, the current consumption can be reduced from 15 mA to 5 mA, and can be reduced to 1/3.

FIG. 3 is a diagram showing a ring waveform when the load of the ring circuit of the telephone is heavy. When the initial values of the ring voltage and the supply current of the ring signal are -180 V / 15 mA and the threshold value is -120 V, the voltage detection circuit 1
5 detects -120 V or less and sends a signal to the control circuit 16. In this case, the control circuit 16 first determines that the load on the telephone is light, and sets the constant current value of the constant current circuit 17 to 10 m.
Change to A. However, when 10 mA is supplied, the voltage detection circuit 15 has −120
When the voltage is equal to or higher than V, a signal is sent to the control circuit 16 again.
The control circuit 16 determines that the telephone load is heavy this time,
The value of the constant current of the constant current circuit 17 is changed to 15 mA and maintained. The above-described ring voltage, the threshold value of the ring voltage, the supply current of the ring signal, and the technique of selecting the supply current are merely examples, and may be arbitrary.

[0019]

As described above, according to the present invention, the terminal voltage of a telephone set at the time of transmitting a ring signal is monitored and detected, and the duplication of the ring waveform is determined by comparing it with a predetermined threshold value. When the load on the ring circuit of the telephone is light, the current consumption can be reduced by reducing the supply current of the ring signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of processing according to the embodiment of the present invention.

FIG. 3 is a diagram showing the timing of a ring waveform when the load on the ring circuit of the telephone is light;

FIG. 4 is a diagram showing the timing of a ring waveform when the load of the ring circuit of the telephone is heavy.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 telephone control circuit 11 -48 V power supply / ring signal transmission circuit 12 communication circuit 13 switch circuit 14 polarity inversion circuit 15 voltage detection circuit 16 control circuit 17 constant current circuit 18 ring signal transmission circuit

Claims (7)

[Claims] When a ring signal for ringing a telephone is transmitted, the magnitude of the load of a ring circuit built in the connected telephone is detected and determined by detecting the voltage of a terminal of the telephone, so that the load of a light load is reduced. In this case, the current supplied when transmitting the ring signal is reduced, and the supplied current is maintained at a predetermined value when the load is heavy. 2. A telephone control circuit for interfacing with a telephone and transmitting a ring signal for ringing a telephone, a power supply for supplying a predetermined constant current superimposed on the ring signal, and a telephone supplied from the power supply. A voltage detector for monitoring and detecting the voltage at the terminal, and comparing the value detected by the voltage detector with a predetermined threshold value, and when the detected value is lower than the threshold value, a built-in telephone is connected. When it is determined that the load of the ring circuit is light, the constant current supplied from the power supply unit is reduced, and when the detected value is higher than the threshold value, it is determined that the load of the ring circuit is heavy and the constant current supplied from the power supply unit is determined. A control unit for maintaining a current at a predetermined value. 3. A power supply / ring having a constant current circuit for supplying a predetermined constant current from a plurality of types to a telephone and a ring signal transmission circuit for superimposing the constant current and transmitting a ring signal for ringing the telephone. A signal transmission circuit, a communication circuit forming a communication path, a switch circuit for switching between the power supply / ring signal transmission circuit and the communication circuit, and a polarity inversion circuit for inverting the polarity of a line connected to the telephone And a voltage detection circuit for detecting a voltage at a telephone terminal supplied from the power supply / ring signal transmission circuit, and comparing a detection value detected by the voltage detection circuit with a predetermined threshold value to a telephone connected. The load of the built-in ring circuit is determined, and as a result, when the detected value is lower than the threshold value, it is determined that the load of the ring circuit is light and supplied from the constant current circuit. A control circuit that reduces the constant current and determines that the load on the ring circuit is heavy when the detected value is higher than the threshold value, and maintains a constant current supplied from the constant current circuit at a predetermined value. Telephone control circuit. 4. The telephone control circuit according to claim 3, wherein said constant current circuit outputs a current in an arbitrary predetermined step. 5. A telephone control method for interfacing with a telephone and controlling transmission of a ringing signal for telephone ringing on which a predetermined constant current is superimposed, wherein an incoming call is detected, a predetermined ring signal is transmitted to the telephone, and a voltage of a terminal of the telephone is detected. And compares the detected value with a predetermined threshold value to determine the load on the ring circuit incorporated in the connected telephone. When the detected value is lower than the threshold value, When the load is determined to be light, the constant current to be supplied is reduced, and when the detected value is higher than the threshold value, the load of the ring circuit is determined to be heavy and the constant current to be supplied is maintained at a predetermined value. Telephone control method to do. 6. The telephone control method according to claim 5, wherein the constant current value outputs a current in an arbitrary predetermined step. 7. A terminal adapter comprising the telephone control circuit according to claim 1.