JPS5929019B2 - Subscriber line signal generation and transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system for transmitting subscriber line signals, such as transmitting a ringing signal from a station to a subscriber, and transmitting a howler sound when a subscriber forgets to remove the handset. In particular, the present invention relates to a subscriber line signal generation and transmission system for use in time-division exchanges and the like where it is difficult to pass high-power subscriber line signals through a switch network.

In the past, little thought had been given to accommodating subscribers directly in a four-wire telephone office.

If the subscriber line signaling system used in conventional two-wire telephone offices were to be followed as is, it would be as shown in FIG. 1, which would require a switching relay to bring the subscriber circuit to the signal source side. These signal sources use a method of superimposing the station's DC power supply in order to detect subscriber responses, but this generally has the disadvantage of creating an unbalanced circuit configuration with respect to the ground, causing station noise. It is also known that when the subscriber line is brought in to the signal source side, the two-wire side of the hybrid circuit becomes open, which worsens the sound point. FIG. 1 is a diagram for explaining a conventional subscriber line signaling system.

In FIG. 1, 1 is a subscriber's house, 2 is a subscriber's line, and 3 is a four-wire telephone office.

4 is a telephone, 5 is a hook switch of the telephone, 6 is a bell, □ is a handset, 8, 9, 14, 15 are relay contacts of the telephone office, 10 is a bell signal sending circuit, and 11 is a ring of the bell signal sending circuit. Trip relay, 12 is 16 ■z power supply, 13
16 is a DC power supply of the station, 16 is a Howler signal sending circuit, 17 is a telephone current supply circuit, 18 and 19 are capacitors, 20 is a hybrid circuit, 21 is a 2-wire to 4-wire conversion circuit 22 of the hybrid circuit 20, and 23 is a transmitting circuit, 2
4 is a receiving circuit, 25 is an audio input terminal, and 26 is an audio output terminal. In FIG. 1, the telephone station 3 sends out a bell signal to call the subscriber by operating a relay (not shown) and drawing the subscriber line 2 into the bell signal sending circuit 10 through its contacts 8 and 9. It is done by twisting. Bell signal current is relay contacts 8, 9, 14, 15, subscriber line 2
The signal then reaches the subscriber's home 1 and rings the bell 6 of the telephone 4. When the subscriber picks up the handset 7 and answers, the hook switch 5 closes. As a result, the DC current sent from the local DC power supply 13 in the bell signal sending circuit 11 is transmitted to the transceiver □
The signal is returned to the bell signal sending circuit to operate the ring trip relay 11, and its contacts (not shown) notify the central office that the subscriber has responded.

As a result, the telephone office restores the relay contacts 8 and 9 and switches the subscriber circuit to a talking state. Telephone current supply circuit 1
7 supplies current to the subscriber's handset 7, and the subscriber's voice communication current driven thereby is transmitted to the subscriber line 2,
Relay contacts 8, 9, 14, 15, telephone current supply circuit 1
7. Hybrid circuit 2 via capacitors 18 and 19
The signal is converted into a 4-wire system by a 2-wire to 4-wire conversion circuit 21 and received by a receiving circuit 24. Next, the voice communication current from the telephone office side is converted into a two-wire system in a 2-wire to 4-wire conversion circuit 21 connected to the output of the transmitting circuit 23, and at the same time is connected to the subscriber line 2 through a balanced connection network 22. It is balanced and reaches the telephone 4 at the subscriber's home via the capacitors 18 and 19, the telephone current supply circuit 17, the relay contacts 8, 9, 14, and 15, and the subscriber line 2.

The subscriber line 2 is drawn in by the relay contacts 14 and 15.The back signal sending circuit 16 sends out an alarm signal from the telephone office to the subscriber if the subscriber forgets to hang up the handset 7 at the end of a call. The system performs a similar operation except that the transmission frequency is different in order to cause the handset to ring, and when the subscriber hangs up the handset, the transmission of the Howrah signal is stopped. However, in such a subscriber line signaling system, a relay is used to bring the subscriber circuit into the signal sending circuit, and a ring trip relay is used to detect the subscriber's response.
This makes it difficult to downsize and save money, and the signal transmission circuit generally has an unbalanced circuit configuration with respect to the ground, which causes (telephone) station noise and also causes the subscriber line to become unbalanced. When connecting to the sending circuit side, the two-wire side of the hybrid circuit becomes open, which has the disadvantage of worsening the sound point.

An object of the present invention is to eliminate the relay for detecting a relay response, which is provided in the conventional signaling system for subscribers to switch the subscriber circuit on the signal source side, thereby realizing miniaturization, economicalization, and improvement in transmission quality. This provides a subscriber signal transmission system that allows

That is, the present invention generates and transmits a bell signal and a howler signal to the subscriber telephone by inverting the polarity of the DC output supplied from the station to the subscriber telephone at a predetermined speed. The present invention will be explained in detail below with reference to the drawings. FIG. 2 shows an embodiment of the subscriber line signal generation and transmission system according to the present invention.

In FIG. 2, the same parts as in FIG. 1 are given the same reference numerals. In FIG. 2, a 2-wire to 4-wire conversion circuit 211 is composed of a diode section 27 of a photocoupler and resistors 28, 29, and a receiving circuit 24/ is composed of a diode section 27 of a photocoupler.
The voice communication current is output to the voice output terminal 26 and the subscriber's response signal is output to the subscriber response signal output terminal 32. Further, 30 is a semiconductor switch having a function of arbitrarily reversing the connection polarity between the station side and the subscriber line;
is a polarity reversal clock input terminal which gives a reversal command to the semiconductor switch 30. The semiconductor switch 30 repeats the polarity reversal operation at this polarity reversal quack speed. 33 is an inhibit gate, which allows the receiving circuit 24' to be activated when the subscriber responds.
The subscriber response signal output inhibits the polarization clock input.

Power is supplied to the subscriber telephone from the local DC power supply 13 via the resistor 34, the semiconductor switch 30, and the subscriber line 2, and reaches the subscriber telephone 4.The return route is via the subscriber line 2, the semiconductor switch 20, and the line 2-4. Line conversion circuit 2 ", Transmission circuit 2
Reflux through 3/. The operation will be explained below with reference to FIG. As shown in FIG. 2, when a clock pulse of 32 mm/sec is applied to the polarity inversion clock input terminal 31 at the telephone office 3 in order to call a subscriber, this pulse passes through the inhibit gate 33 and is applied to the semiconductor switch 30. It will be done.

As a result, the semiconductor switch 30 repeatedly inverts the connection polarity between the office side and the subscriber line, and generates a 16 Hz bell signal. This bell signal reaches the subscriber's house 1 via the subscriber's line 2 and causes the bell 6 of the telephone 4 to ring. When the subscriber takes off the handset 7 and answers, the diode section 27 of the photocoupler of the 2-wire to 4-wire conversion circuit 2 on the telephone office 3 side detects the change in the sending current of the station caused by the closing of the switch 5. is captured and outputted to the subscriber response signal output terminal 32 by the receiving circuit 241.

This prepares the station to enter the talking state. Further, this output is branched and supplied to the inhibit gate 33 to inhibit the clock input from the polarity inversion clock input terminal. As a result, the semiconductor switch 30 stops its polarity reversing operation, and the local DC power supply 13 starts supplying DC current to the telephone set 4. The subscriber's voice communication current driven by the supply current from this station passes through the subscriber line 2,
It reaches the telephone office 3, is converted into a 4-wire system by the 2-wire to 4-wire conversion circuit 21', and is converted into a 4-wire system by the photocoupler's diode section 27.
The signal is transmitted to the receiving circuit 24/ and output to the audio output terminal 26. Next, the voice communication current from the telephone station 3 side is applied to the voice input terminal 25, and at the output of the transmitting circuit 23/2
It is converted into a two-wire system by the line-to-four-wire conversion circuit 21/, and at the same time balanced with the subscriber line 2 by the balanced connection network 22, and reaches the telephone 4 in the subscriber's home 1 via the subscriber line 2.

Regarding the operation of sending out the Haulah signal, the condition on the subscriber side is that the switch 5 of the telephone is closed.

The operation is the same except that the frequency of the signal sent from the station to alarm the receiver is different, so the explanation will be omitted. As described above, the present invention has an economical effect of eliminating the need for a group of relays that were conventionally provided for subscribers, as well as miniaturization and simplification. Reduces station noise caused by noise, relay operation, and noise caused by transient phenomena during recovery.
Furthermore, it is possible to improve transmission quality by increasing the sound margin.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining a conventional subscriber line signal system, and FIG. 2 is a block diagram illustrating a configuration showing an embodiment of the subscriber line signal generation and transmission system according to the present invention. 1...Subscriber's home, 2...Subscriber line,
3...4-wire telephone, 4...telephone,
5...Full switch, 6...Bell,
7...Transmitter/receiver, 13...Station DC power supply,
2 ``...hybrid circuit, 21'...
・2-wire to 4-wire conversion circuit, 22... Balanced connection network,
23/...Transmission circuit, 24'...Reception circuit, 25...Audio input terminal, 26...
・Audio output terminal, 27...Photocoupler diode section, 28, 29...Resistor, 30...
...Semiconductor switch, 31...Polarization reversal clock input terminal, 33...Subscriber response signal output terminal, 3
3...Inhibit gate, 34...
resistance.

Claims (1)

[Claims] 1. A changeover switch is provided between the subscriber line and the hybrid circuit consisting of a 2-wire to 4-wire conversion circuit, a transmitter circuit, a balanced connection circuit, and a receiver circuit, and the switch is switched with a polarity reversal clock pulse to By reversing the polarity of connection with the subscriber circuit, a bell signal and a howler signal are sent out, and a change in direct current due to the subscriber's response is detected by a receiving circuit optically coupled to the 2-wire to 4-wire conversion circuit. A subscriber line signal generation and transmission system characterized in that transmission of the polarity inversion clock is stopped by this.