JPH0461454A - Duplex relay amplifier - Google Patents

Abstract

PURPOSE:To attain not only duplex relay transmission of an AC signal but also duplex relay transmission of a DC signal by providing a DC signal control section relaying and sending a DC pulse signal in duplex to the duplex relay amplifier. CONSTITUTION:A transmission reception amplifier section 2 makes relay transmission an AC signal in duplex. As to duplex relay transmission of a DC signal, a DC signal control section 18 applies ON/OFF control to a line loop forming section 20 in response to the detection of DC interruption at the side of a telephone set, sends a DC pulse generated from the telephone set to a cable and applies ON/OFF control to a terminal loop forming section 21 in response to the detection of DC interruption from the cable to sends the DC pulse from the cable to the telephone set and controls a terminal polarity inversion section 23 in response to the detection of the polarity of the DC voltage at the cable so as to control the polarity of the DC voltage fed to the telephone set. Thus, not only duplex relay transmission of an AC signal but also duplex relay transmission of a DC signal is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bidirectional relay amplifier that is connected to a telephone line that connects a telephone set and a subscriber cable.

If the distance between a telephone and the exchange that accommodates it is too long, transmission loss in subscriber lines and relay systems will increase, resulting in poor communication quality. In such cases, a bidirectional relay amplifier is interposed in the telephone line connecting the telephone and the subscriber cable to compensate for the transmission loss.The present invention relates to a bidirectional relay amplifier used in this sense. It is.

[Conventional technology]

A technology that compensates for cable loss by amplifying AC signals on a two-wire telephone line and relaying them in both directions uses two lines of a two-wire telephone line to amplify AC signals and transmit them in both directions. Since a forwarding telephone device is known, this forwarding telephone device will be described below as a prior art, although it differs in nuance from the above-mentioned two-way relay amplifier device in a strict sense.

FIG. 3 is a block diagram showing a transfer telephone device as an example of a conventional bidirectional relay amplifier device.

In the figure, 15 is an exchange, 13 is a receiving side cable (
1 is a transfer telephone device, and 14 is a transfer destination cable (two-wire telephone line). That is, when the user is absent from the seat he/she always attends, the forwarding telephone device 1 is set and the forwarding destination telephone number that the user wants to be forwarded to is registered in the forwarding destination telephone number storage section 6 therein. The system is such that all calls made to your desk are forwarded to the forwarding destination.

In the transfer telephone device 1, 2 is a transmitting/receiving signal amplifying section, 3 is a transfer control circuit, 4 is an incoming call detection circuit, 5 is a call end detection circuit,
6 is a forwarding destination telephone number storage unit, 7 is a partner response detection circuit, 8
is a dial signal generation circuit, and SWI and SW2 are changeover switches. In the transmitting/receiving signal amplifying section 2, 9A, 9B
are two-wire and four-wire conversion circuits, respectively, IOA and IOB are balanced circuit networks, 11 is a transmitting signal amplifying circuit, and 12 is a receiving signal amplifying circuit.

The circuit operation will be explained below. When a call arrives at the transfer telephone device 1 from the incoming call cable 13, the incoming call detection circuit 4 detects this and notifies the transfer control circuit 3, and the transfer control circuit 3 captures the transfer destination cable 14.

Next, the transfer control circuit 3 causes the dial signal generating circuit 8 to generate a dial signal corresponding to the transfer destination telephone number registered in advance in the transfer destination telephone number storage section 6, and transmits the dial signal to the transfer destination.

When the transfer destination subscriber responds, the other party response detection circuit 7 operates, and upon receiving this, the transfer control circuit 3 switches the changeover switch S.
The WI and SW2 are closed, and the receiving side cable 13 and the transfer destination cable 14 are connected via the transmitting/receiving signal amplifying section 2.

Therefore, AC signals such as voice coming from the receiving side cable 13 are amplified by passing through the 2-wire 4-wire conversion circuit 9A, the received signal amplification circuit 12. Transmitted and destination cable 1
Conversely, AC signals such as voice coming from the receiving side cable 1 are amplified by passing through the 2-wire 4-wire conversion circuit 9B, the transmitting signal amplification circuit 11.
3.

[Problem to be solved by the invention]

In the transfer telephone device as an example of the conventional two-way relay amplifier device described above, the transmission of the dial pulse signal, which is a DC pulse signal, is carried out in advance by the transfer destination telephone number storage unit 6.
The system uses a dial signal generating circuit 8 to send out the forwarding destination telephone number registered in the forwarding destination cable 14 to the forwarding destination cable 14, and does not have a means for directly relaying the DC signal.

For this reason, even if such transfer telephone equipment is used as a bidirectional relay amplifier that is connected to the telephone line that connects the telephone and the subscriber cable, the dialing signal sent from the telephone after the line is connected, DC signals such as pulse signals, polarity reversal signals, billing pulse signals, etc. sent from the exchange cannot be relayed to the other party, so they cannot be used.

The present invention solves such problems and is a bidirectional relay amplifier that is connected to a telephone line that connects a telephone set and a subscriber cable. It is an object of the present invention to provide a bidirectional relay amplifier capable of not only relaying transmission, but also relaying and transmitting DC signals such as dial signals, hooking pulse signals, polarity reversal signals, billing pulse signals, etc. to the other party.

[Means to solve the problem]

To achieve the above object, the present invention includes an incoming signal amplification circuit that amplifies the AC incoming signal from the subscriber cable and sends it to the telephone, and an incoming signal amplification circuit that amplifies the AC outgoing signal from the telephone. a transmitting/receiving amplifying section including a transmitting signal amplifying circuit for sending out to the subscriber cable; a line DC current detecting section;
A bidirectional relay amplifier was constructed by a terminal DC current detection section, a line loop formation section, a terminal loop formation section, a line polarity detection section, a terminal polarity inversion section, and a DC signal control section.

[Effect]

The transmitting/receiving amplifying section bidirectionally relays and transmits the AC signal.

Regarding bidirectional relay transmission of DC signals, the DC signal control section functions as follows.

That is, when the terminal DC current detection section detects an interruption in the direct current on the telephone side, the DC signal control section controls the line loop forming section on and off accordingly, and directs the DC pulses generated on the telephone side to the cable side. When the line DC current detection section detects the interruption of direct current on the sending and cable side,
Accordingly, the terminal loop forming section is controlled on and off to send a DC pulse from the cable side to the telephone side, and when the polarity of the cable side DC voltage is detected by the line polarity detection section, the terminal polarity is inverted accordingly. control the polarity of the DC voltage supplied to the telephone side.

In this way, in the bidirectional relay amplifier according to the present invention, not only bidirectional relay transmission of AC signals (but also bidirectional relay transmission of DC signals) is possible.

〔Example〕

The present invention will now be described in detail with reference to the drawings.

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

In this figure, the same elements as in FIG. 3 are given the same reference numerals. Others, 27 are subscriber cables, 16
2 is a bidirectional relay amplifier according to the present invention, 2 is a telephone,
It is. In the bidirectional relay amplifier 16, 17 is a line DC current detection section, 18 is a DC signal control section, 19 is a terminal DC current detection section, 20 is a line loop formation section, 2] is a terminal loop formation section, and 22 is a line polarity. 23 is a terminal polarity reversing unit, 24 is a power supply unit, 25 is an incoming call detection unit, and 26 is a power outage detection unit.

Hereinafter, the circuit operation will be explained by taking as an example the case where a call is made from the telephone set 28 in FIG.

Before that, when commercial power is supplied to the power supply section 24,
The DC signal control unit 18 detects this by means not shown and switches the changeover switches SW3 and SW4 to the OFF side to allow direct communication between the telephone 28 and the incoming call detection unit 25, and also connects the terminal loop forming unit 21. Off: The line loop forming section 20 is turned off, and a switching timer (not shown) that monitors the off-state duration of the terminal DC current detecting section 19 is reset to an initial state.

To reset and restart the switching timer,
As will be described later, there are cases where the terminal DC current detection unit 19 turns on and off and turns off temporarily, and cases where it turns off not temporarily but finally turns off. is determined from the time limit of the timer, and the DC signal control unit 1
3 is to avoid any hindrance to the next control operation.

Next, when the telephone 28 goes off-hook to make a call, a DC current flows through the subscriber cable 27, and the line DC current detection section]
7 is turned on. When the DC signal control unit 18 detects that the line DC current detection unit 17 is turned on, it switches the changeover switches SW3 and SW4 to the on side to turn on the telephone 28.
A necessary part of the bidirectional relay amplification bag W16 is interposed between the terminal loop forming section 21 and the incoming call detection section 25, and the terminal loop forming section 21 is turned on.

Therefore, a communication current is supplied from the power supply section 24 to the telephone 28 . When a DC current flows through the telephone 28, the terminal DC current detection section 19 turns on, and the DC signal control section 18
Detecting that the terminal DC current detection section 19 is turned on, the line loop forming section 20 is turned on, and the subscriber cable 27 is turned on.
Loop the line on that side.

Next, the dial tone sent from the exchange 15 is an AC signal, so the subscriber cable 27 → line DC current detector 17 → incoming call detector 25 → switch SW 3 (on (l)
) → line loop forming unit 20 → 2-wire 4-wire conversion circuit 9A → received signal amplification circuit 12 → 2-wire 4-wire conversion circuit 9B → switch SW4 (on side).
sent to.

The next PB dial signal sent from the telephone 28 is from switch SW4 (on side) to 2-wire 4-wire conversion circuit 9B.
→ Sending signal amplification circuit 11 → 2-wire 4-wire conversion circuit 9A → Line loop forming unit 20 → Sui Nochi SW 3 (on side) → Incoming call detection unit 25 → Line direct fL current detection unit 17. is sent to the user cable 27 side.

If the dial signal sent from the telephone 28 is not an AC PB signal but a DC dial pulse signal, the direct current on the telephone 28 side is intermittent, so the terminal surface '& current detection section 19 detects the dial pulse signal. Turns on in sync with the signal,
Repeat off. When the DC signal control unit 18 detects that the terminal DC current detection unit 19 is turned off, the DC signal control unit 18 turns off the line loop formation unit 20, and turns off the terminal DC current detection unit 19.
9 is turned on, the line loop forming section 20 is turned on and the same DC pulse signal as the dial pulse signal sent from the telephone 28 side is regenerated and the switch 1
Send to the 5th side.

Next, when the exchange 15 receives the PB dial signal or the DC dial pulse signal from the telephone set 28 and calls the subscriber on the other side, a ringing tone is sent out from the exchange 15. Since this signal is an alternating current signal, it is amplified by the reception signal amplification circuit 12 in the transmission/reception amplification section 2 and sent to the telephone 28 side as a ringback tone.

When the other subscriber goes off-hook in response to the ringing tone from the exchange 15, the polarity of the DC supplied from the exchange 15 is reversed, so the line polarity detector 22 detects this and receives a DC signal notified of this fact. The control unit 18 operates the terminal polarity inversion unit 23 to invert the polarity of the direct current supplied to the telephone 28 .

When the call state is entered, the call voice signals coming from the subscriber cable 27 side and the telephone set 28 side are amplified in each direction by the transmitter/receiver amplifier 2 and transmitted to the other party. Furthermore, when a hooking operation is performed on the telephone 28 during a call, the direct current of the telephone 28 is temporarily repeatedly turned off, so that the terminal direct current detection section 19 is repeatedly turned off accordingly.

The DC signal control unit 18 detects this and causes the line loop forming unit 20 to repeatedly turn off, thereby transmitting the hooking pulse signal to the subscriber cable 27 side.

When the telephone call ends and the telephone 28 goes on-hook, the terminal DC current detection section 19 turns off, and the DC signal control section 18 detecting this turns off the line loop formation section 20.

As mentioned above, the line loop forming unit 20 can be turned off temporarily by intermittent operation depending on the on/off DC pulse of the telephone 28, or finally turned off when the call ends. However, the DC signal control section 1
8 starts a timer (not shown) each time the line loop forming unit 20 is turned off, and if the line loop forming unit 20 returns to on within a certain period of time, the off time is temporarily turned off. If the timer determines that the line loop forming unit 20 has not been turned back on even after a certain period of time, it is determined that the turn off at that time is not temporary (it is a final turn off). In other words, in this case, when the line loop forming section 20 is finally turned off, the DC signal control section 18
When the determination is made, the changeover switches SW3 and SW4 are turned back to the OFF side to return to the initial state.

The above is an explanation of the operation when a call is made from the telephone 28, but the operation when a call is received at the telephone 28 will be explained as follows.

When the incoming call signal 167 arrives from the exchange 15, the incoming call detection section 25 turns on, and at the same time, the line DC current detection section 17
repeats on and off in sync with the incoming signal. When the DC signal control unit 18 detects that the incoming call detection unit 25 is turned on, the DC signal control unit 18 maintains the changeover switches SW3 and SW4 in the OFF state even if the line DC current detection unit 17 is turned on, and the DC signal control unit 18 maintains the changeover switches SW3 and SW4 in the OFF state even if the line DC current detection unit 17 is turned on. The incoming call signal is directly connected to telephone 2.
8, thereby causing the incoming circuit of telephone 28 to ring.

When the telephone 28 responds and goes off-hook, the same operation as described above when making a call will be performed.

If the commercial power supply that supplies power fails during operation, the power failure detection unit 26 detects this and forcibly returns the changeover switches SW3 and SW4 to the OFF state. It is possible to make a direct connection between the telephone 28 and the telephone 28 to ensure other functions except the AC signal amplification operation. When this power outage is detected, switch SW3
The operation of forcibly turning off SW4 is performed by switching SW4.
This can be easily realized by using relays or the like as SW3 and SW4. Furthermore, it goes without saying that this device can also be operated using a power source such as a battery instead of a commercial power source.

The operation of the embodiment of the present invention described above is summarized in the flowchart of FIG. 2, and will be better understood by referring to the flowchart.

〔Effect of the invention〕

According to the present invention, as explained above, AC signals such as voice signals arriving from the cable side and the telephone side are respectively amplified and transmitted to the other party, and at the same time, various DC pulses arriving from the cable side and the telephone side are amplified and transmitted to the other party. There is an advantage in that a bidirectional relay amplifier device that can also relay signals to the other party can be provided.

The bidirectional relay amplifier according to the present invention can be used by being interposed between a telephone set that transmits and receives a DC pulse signal such as a DC dial pulse signal and a subscriber cable, and thereby can be used regardless of the loss in the subscriber cable. This has the advantage of making it possible to always talk at a comfortable volume on the phone.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flowchart showing the operation of an embodiment of the present invention,
FIG. 3 is a block diagram showing a transfer telephone device as an example of a conventional bidirectional relay amplifier device. Explanation of symbols 2... Transmission/reception amplification unit, 16... Bidirectional relay amplifier device according to the present invention, 17... Line DC current detection unit, 18
...DC signal control section, 19 river terminal DC current detection section, 2
0... Line loop forming section, 21... Terminal loop forming section, 22... Line polarity detection section, 23... Terminal polarity inversion section, 24... Power supply section, 25... Incoming call detection Department,
26... Power outage detection section, 27... Subscriber cable, 2
8...Telephone agent Patent attorney Akio Namiki

Claims (1)

[Claims] 1) In a bidirectional relay amplification device that is connected to a telephone line that connects a telephone and a subscriber cable, an AC received signal from the subscriber cable is amplified and sent to the telephone. a transmitting/receiving transmitting/receiving amplifying section that bidirectionally relays and transmits the alternating current signal by including a receiving signal amplifying circuit for amplifying the alternating current transmitting signal from the telephone and transmitting the amplified signal to the subscriber cable; , a line DC current detection unit, a terminal DC current detection unit, a line loop formation unit, a terminal loop formation unit, a line polarity detection unit, a terminal polarity inversion unit, and a DC signal control unit on the telephone side. When the terminal DC current detection section detects an interruption in the DC current, the circuit loop forming section is controlled to turn on or off accordingly, and the DC pulse generated on the telephone side is sent to the cable side, thereby preventing the interruption of the DC current on the cable side. When detected by the line DC current detection unit, the terminal loop forming unit is controlled on and off accordingly to send a DC pulse from the cable side to the telephone side;
When the polarity of the DC voltage on the cable side is detected by the line polarity detection unit, the terminal polarity reversal unit is controlled accordingly to control the polarity of the DC voltage supplied to the telephone side, thereby relaying and transmitting the DC pulse signal in both directions. A bidirectional relay amplifier, comprising: the DC signal control section.