JPH09247298A - Electricity feeding system for subscriber circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy the on-hook communication function of a subscriber circuit and also satisfy the national laws and regulations, and communicate with all private branch exchanges and terminal machines without raising a source voltage. SOLUTION: A terminal machine 9 which requires a line-to-line open voltage higher than a specific value is powered by an electricity feeding circuit A3 at its origination monitor time and by an electricity feeding circuit B4 at its telephone calling time. A relay 8 switches connections between the electricity feeding circuits A3 and B4, and terminal machine 9. A relay control circuit 7 drives and controls a relay 8 according to two kinds of origination detection signal (SCNA signal and SCNB signal) received from the electricity feeding circuit A3 or the SCN signal received from the electricity feeding circuit B4. A CODEC 5 converts an analog speech signal from the terminal machine 9 after 2-line/4-line conversion by the electricity feeding circuit B4 into a digital speech signal and an LSI 6 processes the digital speech signal from the CODEC 5 to generate a PCM signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system for a subscriber circuit, and in particular, it is connected to a telecommunication equipment for a carrier and a private branch exchange defined in the Telecommunications Carrier Regulations of Type 1 Telecommunications Carriers in Japan. The present invention relates to a power supply system for a subscriber circuit in a digital exchange.

[0002]

2. Description of the Related Art As an example of a conventional subscriber circuit of this type, there is a "subscriber circuit" disclosed in Japanese Patent Laid-Open No. 3-62065.

FIG. 4 is a block diagram showing an example of a conventional power supply system for a subscriber circuit, which is equivalent to the block diagram of the embodiment circuit described in the above publication.

Referring to FIG. 4, between the terminal 1 of the two-wire subscriber line connected to the terminal 9 and the power supply potential for supplying the call current and the other terminal 2 of the two-line subscriber line. And a ground potential, a series circuit of a power feeding resistor 401 and a power feeding transistor circuit 405, and a power feeding resistor 40, respectively.
2 and a power supply transistor circuit 406 are connected in series, and a differential input voltage amplifier 407 to which the potential between the terminals 1 and 2 is input, and a DC voltage corresponding to the output of the differential input voltage amplifier 407 are generated. And a feeding impedance combining circuit 408
It is provided with two drive circuits 413 and 414 which are feedback-connected through impedances 409 and 410, respectively, so as to branch the outputs of the eight outputs and drive the control inputs of the power supply transistor circuits 405 and 406.

In this conventional example, the power supply transistor circuits 405 and 406 are constructed such that complementary polarity type transistors are push-pull connected between the power supply voltage terminals 403 and 404 and the ground potential (ground), respectively. Have

Further, the feeding impedance combining circuit 408
A control current source 412 is provided to supply a control current to the drive circuits 413 and 414, which is superimposed on the output of the control current source 412.

Further, when the voltage across each of the resistors 401 and 402 for power supply is input and the voltage across the terminals 9 of the terminals 9 connected to the pair of terminals 1 and 2 is a voltage in an on-hook state, it is used for control. The current source 412 supplies a control current to the drive circuits 413, 414, and the control current source 412 is provided so that each drive circuit 413, 414 gives a DC bias voltage lower than that at the time of supplying the call current between the pair of terminals 1, 2. A loop current discrimination circuit 411 for controlling is provided.

Therefore, the power supply system for the subscriber circuit according to this conventional example is effective even when the terminal is on-hook.
A DC bias voltage was supplied to eliminate noise in the induced voltage due to the common-mode potential, enabling signal transmission during on-hook.

[0009]

However, in this conventional power supply system for the subscriber circuit, a DC bias is used to perform communication other than communication such as noise elimination of line open circuit voltage during on-hook and remote meter reading. A voltage was provided, and the line open voltage when on-hook was several volts lower than the absolute value of the power supply voltage was supplied to the terminal.

Assuming that the power supply voltage is -43V, the telecommunications equipment regulation for operators in Japan, Section 5 Analog telephone equipment, Article 27, satisfies the open circuit voltage of 42V or more and 53V or less. There was a problem that I could not do it.

Also, depending on the private branch exchange to be connected,
The open circuit voltage between lines is monitored to confirm the normality of the subscriber line, and the monitored voltage may be 40V or more. Therefore, in the conventional subscriber circuit, there is a problem in that it is necessary to boost the power supply voltage for the private branch exchange, which increases the power consumption of the entire apparatus.

An object of the present invention is to satisfy the on-hook communication function of a subscriber circuit, satisfy domestic laws and regulations, and enable communication to all private branch exchanges and terminals without boosting the power supply voltage. It is to provide a power supply system for a subscriber circuit.

[0013]

According to the present invention, a first power supply circuit for supplying power to a terminal device requiring a line open circuit voltage of a predetermined value or more at the time of call origination monitoring, and to the terminal device. A second power supply circuit that supplies power during the call, a switching unit that switches between the first power supply circuit and the second power supply circuit, and a control circuit that drives and controls the switching unit. It is possible to obtain a power supply system for the operator circuit.

In the subscriber circuit power feeding method, the first power feeding circuit feeds the line open circuit voltage substantially equal to a power supply voltage to the terminal when the terminal monitors the call. can get.

Further, when the control circuit recognizes that two types of call detection signals having different voltage values are output from the first power supply circuit, the first power supply circuit outputs the second call detection signal.
A power supply system for a subscriber circuit is obtained, which is characterized in that switching control to the power supply circuit is performed.

Further, the control circuit controls switching from the second power supply circuit to the first power supply circuit at a predetermined timing from the time when the terminal goes on-hook. It is possible to obtain a power supply method for a subscriber circuit that operates.

[0017]

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

FIG. 1 is a block diagram showing an embodiment of a power feeding system for a subscriber circuit of the present invention, FIG. 2 is a circuit diagram showing an example of a power feeding circuit A in FIG. 1, and FIG. 3 is a relay control circuit in FIG. It is a circuit block diagram of an example.

Referring to FIG. 1, the subscriber circuit power feeding method according to the present embodiment is a first power feeding circuit that feeds power to a terminal 9 that requires a line open circuit voltage of a predetermined value or more during call origination monitoring. (Power feeding circuit A) 3, a second power feeding circuit (power feeding circuit B) 4 that feeds power to the terminal 9 during the call, a relay 8 as a switching unit that switches between the power feeding circuit A3 and the power feeding circuit B4, and power feeding Two types of call detection signals (SCNA, SCNB) from circuit A3 or SC from power supply circuit B4
A relay control circuit 7 that receives an N signal to drive and control a relay 8, a codec 5 that converts an analog audio signal from the terminal 9 that has been converted into two-wire / four-wire by the power supply circuit B4 into a digital audio signal, and this codec LSI 6 which processes the digital audio signal from the signal 5 into a PCM signal.

That is, the present embodiment is configured to switch the power feeding method according to the state of the terminal device 9, and is connected to the power feeding circuit A3 when the terminal device 9 is in the on-hook state, that is, during call monitoring. , The terminal 9 is connected to the power supply circuit B4 when the terminal 9 is in the off-hook state, that is, during a call.

Here, the power supply circuit B4 is similar to the conventional power supply circuit, and is a circuit capable of supplying a voltage lower than the absolute value of the power supply voltage by a few volts to the terminal 9 through the contact 8a (broken line) and performing on-hook communication. is there.

Further, the relay control circuit 7 performs autonomous control (control by the SCNA signal and SCNB signal from the power feeding circuit A3 and the SCN signal from the power feeding circuit B4) and program control (program control signal (CTL from the control terminal 10).
Signal) control).

Further, the LSI 6 processes the digital voice signal and data from the codec 5.

Next, referring to FIG. 2, the power supply circuit A3 includes a resistor R301 for power supply between the terminal 1 of the pair of terminals 1 and 2 of the subscriber line and the power supply potential V for supplying the call current. A high resistance resistor R305 is connected in parallel through a transistor Tr303, and a transistor Tr304 is connected in parallel with a power feeding resistor R302 between the terminal 2 and the ground potential G.
A resistor R306 having a high resistance value is connected through.

Further, the transistor Tr307 for making the operating potential of the terminal 1 the same as that of the terminal 2 is the transistor T307.
It is connected to r303. And the transistor Tr
Resistors R308 and R309 connected to 307 and resistors R310 and R31 connected to the transistor Tr304
1 makes the operating voltage ranges of the transistor Tr307 and the transistor Tr304 constant, respectively.

Comparators CMP312 and CMP313
Also, the comparators CMP314 and CMP315 detect the voltage changes of the transistors Tr304 and Tr307 and convert them into logic signals.

Further, comparators CMP312 and CMP
A comparator C for logic synthesis is provided in the preceding stage of 313.
MP316 and CMP317 are connected.

The resistors R318, R319 and R
320 is a comparator CMP312, ..., CMP315
The voltage threshold of is set.

Next, referring to FIG. 3, the signal input to the relay control circuit 7 is the power supply circuit A3 shown in FIG.
The SCNA signal and the SCNB signal from the power feeding circuit B4, the CTL signal from the control terminal 10,
There is a clock signal (CLK signal) from the outside.

The SCNA signal and the SCNB signal are input to the logic circuit (EXOR) 71 and the logic circuit (NOR) 72, and the output signal from the EXOR 71 is an alarm signal (A
LM signal).

The SCNA and B signals output from the NOR 72 are input to the D terminal of the data holding circuit (F / F) 73 and the logic circuit (AND) 76, and the output signal from the Q terminal of the F / F 73 is data controlled. It is input to the circuit (DTC) 77.

The SCN signal is a data holding circuit (F /
F) is input to the D terminal of 74 and AND76
The output signal from the Q terminal of No. 4 is input to the DTC 77.

Further, a timing generation circuit (CNT) 7 for generating the timing of the relay control signal (RLC signal).
The output timing signal from the Q terminal of No. 5 is input to the DTC 77, and the DTC 77 determines the transmission of the RLC signal depending on the states of the SCNA, B signal and the SCN signal.

The CLK signal is F / F73, F / F7.
4 and CK terminal of CNT75. Also, A
The output of ND76 is connected to the R terminal of CNT75, and the reset signal from DTC77 is input to the R terminal of F / F73 and the R terminal of F / F74.

Next, the operation of this embodiment will be described with reference to FIGS.

When the terminal 9 as the line load resistance is in the on-hook state, the resistances R301 and R3 of the power feeding circuit A3.
05 and the resistors R302 and R306, the power supply potential V
Is applied across terminals 1 and 2. Therefore, the line open-circuit voltage during on-hook (during call monitoring) is the power supply potential V
A voltage substantially equal to the voltage of is supplied to the terminal 9.

When the terminal 9 goes off hook (when making a call)
Are transistors Tr304 and Tr30 of the power supply circuit A3.
7 turns on, and comparators CMP312 and CMP313
A voltage lower than the threshold of is input.

Here, the comparators CMP312 and CM
The comparators CMP316 and CMP317 are set so that the SCNA signal and the SCNB signal are output only when the input voltage of P313 is less than or equal to the threshold voltage.

Further, when a fault occurs in the subscriber line instead of off-hook, that is, when a voltage occurs in only one of the terminals 1 and 2, the comparator CMP314,
A signal is output from the CMP 315.

These SCNA signals and SCNB signals are input to the relay control circuit 7. When both signals are output in active high, the F / F is passed through the NOR 72.
The data is held at 73 and this data is output to the DTC 77.

At this time, the CNT 75 is reset by the output from the AND 76, and when the RTC signal is output from the DTC 77 and the relay 8 operates, the contact 8a (broken line) is connected to the power feeding circuit B4, and the power feeding circuit B4 outputs the SCN signal. Is output as high active. This SCN
The RLC signal is continuously output while the signal is being output.

Next, when the terminal 9 is hooked / hooked, the SCN signal of the power feeding circuit B4 is turned off, the reset of the CNT 75 is released, and counting up is started.

The timing generated by CNT75 is CK
Depending on the CLK signal input to the terminal, in the present embodiment, for example, in order to generate a timing signal of 1 second, 25
A 6 ms CLK signal is used.

The timing signal of 1 second from CNT75 is D
When the signal is input to TC77, the RLC signal turns off, the relay 8 operates, and the terminals 1 and 2 are reconnected to the power feeding circuit A3 through the contact 8a (solid line).

As described above, the reason for taking the timing of 1 second in this embodiment is to prevent the relay 8 from operating due to dial pulse and hooking.

Next, when only one of the SCNA signal or the SCNB signal is output, the ALM signal is output as a line fault through the EXOR 71.

In this embodiment, in order to enable on-hook communication, the relay control circuit 7 has a function of program-controlling the relay 8 with a CTL signal and connecting it to the power supply circuit B4 capable of on-hook communication. It is provided.

As described above, the relay control circuit 7 of this embodiment controls the switching of the relay 8 by the SCNA signal, the SCNB signal and the SC signal from the power feeding circuit A3 and the power feeding circuit B4.
Since both the autonomous control by the N signal and the program control from the control terminal 10 can be performed, on-hook communication is performed even if the terminal 9 requires a line open-circuit voltage when on-hook. Is possible.

[0049]

As described above, according to the present invention, the first power supply circuit for supplying power to the terminal device requiring the line open circuit voltage of the predetermined value or more at the time of call origination monitoring, and the terminal device for the call. By providing a second power supply circuit for occasionally supplying power, switching means for switching between the first power supply circuit and the second power supply circuit, and a control circuit for driving and controlling the switching means, the first power supply circuit is also provided. The circuit supplies the terminal with an open-circuit voltage between lines which is substantially equal to the power supply voltage at the time of monitoring the call origination of the terminal, and the control circuit further provides the two kinds of call detection signals of different voltage values from the first feeder circuit. By controlling the switching from the first power feeding circuit to the second power feeding circuit when the terminal recognizes that the terminal has been output, the control circuit further causes the control circuit to set a predetermined timing from the time when the terminal goes on-hook. Take By controlling the switching from the second power feeding circuit to the first power feeding circuit, the on-hook communication function of the subscriber circuit is satisfied and the domestic laws and regulations are satisfied, without increasing the power supply voltage, that is, the device. The effect that the subscriber circuit can be connected to and communicate with all private branch exchanges and all terminals including terminals requiring line open voltage of a predetermined value or more without increasing the power consumption of Have.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a power supply system for a subscriber circuit according to the present invention.

FIG. 2 is a circuit diagram showing an example of a power supply circuit A in FIG.

FIG. 3 is a circuit block diagram of an example of a relay control circuit in FIG.

FIG. 4 is a block diagram showing an example of a conventional power supply system for a subscriber circuit.

[Explanation of symbols]

1, 2 terminals 3 feeding circuit A 4 feeding circuit B 5 codec 6 LSI 7 relay control circuit 8 relay 8a contact 9 terminal 10 control terminal 71 logic circuit (EXOR) 72 logic circuit (NOR) 73, 74 data holding circuit (F / F) 75 Timing generation circuit (CNT) 76 Logic circuit (AND) 77 Data control circuit (DTC) 301, 302, 305, 306, 308, 309, 3
10, 311, 318, 319, 320 Resistance (R) 303, 304, 307 Transistor (Tr) 312, 313, 314, 315, 316, 317
Comparator (CMP) 401, 402 Power supply resistor 403, 404 Power supply voltage terminal 405, 406 Power supply transistor circuit 407 Differential input voltage amplifier 408 Power supply impedance combining circuit 409, 410 Impedance 411 Loop current discrimination circuit 412 Control current source 413, 414 Drive circuit ALM Alarm signal CLK Clock signal CTL Program control signal G Ground potential PCM PCM signal RLC Relay control signal SCN SCN signal SCNA, SCNB Call detection signal V Power supply potential

Claims (4)

[Claims] 1. A first power supply circuit for supplying power to a terminal device requiring a line open circuit voltage of a predetermined value or more during call monitoring, and a second power supply circuit for supplying power to the terminal device during a call. And a switching means for switching between the first power feeding circuit and the second power feeding circuit, and a control circuit for driving and controlling the switching means. 2. The subscriber according to claim 1, wherein the first power supply circuit supplies the terminal with an open circuit voltage that is substantially equal to a power supply voltage when the terminal monitors the call. Circuit power supply method. 3. When the control circuit recognizes that two types of call detection signals of different voltage values are output from the first power supply circuit, the control circuit moves from the first power supply circuit to the second power supply circuit. 2. The power supply system for a subscriber circuit according to claim 1, wherein the switching control is performed. 4. The control circuit controls switching from the second power supply circuit to the first power supply circuit at a predetermined timing from the time when the terminal goes on-hook. The power supply system for the subscriber circuit according to claim 1.