JPS63164553A - Waiting system for four-wire exchange - Google Patents

Abstract

PURPOSE:To reduce the cost of an equipment by using a pair of channels (Ch) for exclusive origination, using two pairs of channels for exclusive reception, and when one pair of channels out of two pairs are incoming, allowing the the incoming call to other pair Ch to be on standby. CONSTITUTION:A 4-wire type exchange waiting system is constituted of a 4-wire type exchange 1, transmission lines 21-1-21-4, reception lines 22-1-22-4, a facsimile 23 for exclusive transmission, facsimile equipments 24, 27, 31, and a full double units 9-1-9-4 and the exchange 1 is provided with line interface parts 8-1-8-4. If the equipment 31 accesses the equipment 28 when facsimile communication is executed by the equipments 28, 27 in said constitution, the equipment 31 is turned to a waiting state. After the completion of said facsimile communication, the waiting state of the equipment 31 is released and facsimile communication is started between the equipments 28 and 31.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a standby system for a four-wire switch.

(Prior Art) In data communication, for example, facsimile communication, when a data signal is sent from a sender to a receiver, it is common for the receiver to send a response signal to inform the sender of the reception status prior to this. . In this case, if the line used is a two-wire type, the communication will be so-called half-duplex communication in which only either transmission or reception is performed alternately.

On the other hand, if the line used is a 4-wire system, the transmitting line S and receiving line R are each divided by filters, as shown in Figure 2, and full-duplex communication in different directions that allows simultaneous transmission and reception is possible. Become. In other words, the figure shows an example of a telephone line with characteristic A, and the transmitting line S and the receiving line R are provided with a high-pass filter of characteristic port and a low-pass filter of characteristic C, respectively. It is divided into low frequency SL and RL, and is used as a set of 5H-RL and 5L-RH.

That is, when transmitting data from a specific facsimile machine to another facsimile machine, the low frequency S of the transmission line S is
L is used for wideband data signal transmission, and high frequency RH of reception line R is used for receiving response signals (usually FSK signals). Furthermore, when a specific facsimile device receives data from another facsimile device, the low frequency band R of the receiving line 111R is used for data signal reception, and the high frequency band S of the transmitting line S is used for data signal reception.
H is used for response signal transmission.

However, the conventional different-direction full-duplex exchange for performing such different-direction full-duplex communication is special because it incorporates the low-pass filter and high-pass filter, and this special feature makes it expensive and expensive. The scope of use has been narrowed. Furthermore, if a specific facsimile device receives another call while receiving data from another facsimile device, it will not be able to respond to this call. Therefore, the facsimile machine that made the outgoing call in response to the incoming call had to repeatedly disconnect the line and make the outgoing call again.

(Problems to be Solved by the Invention) As described above, the conventional different-direction full-duplex switch is special, and due to this speciality, there have been problems in that it is expensive and its range of use is narrowed. Also, certain terminals cannot respond to other incoming calls when they are in the receiving state, so the terminal that made the call in response to the other incoming call must disconnect the line and make the call again. The drawback was that it had to be repeated.

SUMMARY OF THE INVENTION Therefore, the present invention provides a standby system for a 4-wire switch that is capable of performing full-duplex communication in different directions using a general-purpose 4-wire switch, and that is capable of putting other incoming calls on standby for a receiving terminal. With the goal.

[Configuration 1 of the Invention (Means for Solving the Problems) In the present invention, one line is composed of four wires, and the two wires on the input side and the two wires on the output side are respectively divided into high and low frequencies by filters. split, and provide one set of channels or two sets of channels for the input side high range and the output side low range, and two sets of channels or one set of channels for the input side low range and the output side high range. In the standby system of a 4-wire switch, in which these three sets of channels are exchanged and connected per line using independent switch groups, one set of channels is dedicated to outgoing calls, and the two sets of channels are It is designed to be used only for incoming calls, and if a call is received on one of the two sets of channels and a call is received on the other set of channels, the call is placed on standby for the other set of channels. It is characterized by

(Function) According to the present invention, when a call is received on one of the navy blue channels of channels 21#J dedicated to incoming calls, and a call is received on the other set of channels, the other set of channels receives a call. In order to wait for incoming calls, when communication related to one set of channels is terminated,
Communication regarding the other set of channels can be initiated.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a standby system for a four-wire exchange according to the present invention. In the same figure, 4-wire AC
ii is a general-purpose instant type, and includes a calling side R interface 2 and a calling side T interface 3 corresponding to one set of channels exclusively for outgoing calls, and a receiving side R interface corresponding to one set of channels only for receiving calls. Each line interface unit 8 to 1 to 8-4 is provided, each consisting of a receiving side interface 5, a receiving side R interface 6, and a receiving side T interface 7 corresponding to the other set of channels dedicated to incoming calls. There is. These line interface sections 8-1 to 8-4 each have a full duplex unit 9-1.
9-4 are connected to each other, the transmitting side R interface 2 is connected to the transmitting amplifier 11 via the low-pass filter 10 with the characteristic C shown in FIG. 2, and the transmitting side T interface 3 is connected to the receiving amplifier 12. Connected. Also, the called side R
A high-pass filter 13 and a selector switch 14 with the characteristic shown in FIG. 2 are inserted between the interface 4 and the transmitting amplifier set, and a low-pass filter 15 with the characteristic Changeover switch 16
is inserted. Furthermore, a characteristic high-pass filter 17 and a changeover switch 14 are inserted between the receiving side R interface 6 and the transmitting amplifier set, and a characteristic low-pass filter 18 and a changeover switch 14 are inserted between the receiving side T interface 7 and the receiving amplifier 12. Switch 16 is inserted. Here, the changeover switches 14 and 16 are normally connected to the high-pass filter 13 side and the low-pass filter 15 side. Each of the full-duplex units 9-1 to 9-4 is provided with a control section 19, and the control section 19 controls each selector switch 14 based on the signals transmitted through the 21 sets of channels dedicated to incoming calls. .1
6 and performs channel control.

Now, from the sending-only facsimile machine 23 connected to the full-duplex unit 9-1 via the sending line 21-1 and the receiving line 22-1, the sending port 121-2 and A call is made to the facsimile device 24 connected via the receiving line 22-2 to perform facsimile communication. In this case, 411! In the type exchange 1, the originating side R interface 2 and the originating side T interface 3 of the line interface section 8-1 and the terminating side T interface 5 and the terminating side R interface 4 of the line interface section 8-2 are connected to the first line 25. and a second line 26, respectively. Therefore, the low-frequency data signal output from the transmission-only facsimile device 23 to the transmission line 21-1 is routed through the transmission amplifier 11 → low-pass filter 10 → the originating side R interface 2 → the first line 25 → the receiving side T interface 5. →Low pass filter 15→Selector switch 16→
It is transmitted from the receiving amplifier 12 to the receiving line 22-2 to the facsimile device 24. On the other hand, the high-frequency response signal output from the facsimile device 24 to the transmission line 21-2 is transmitted through the transmission amplifier 11 → selector switch 14 → high-pass filter 13 → called side R interface 4 → second line 26 → calling side T It is transmitted from the interface 3 to the receiving amplifier 12 to the receiving line 22-1.

Next, the facsimile machine 27 connected to the full-duplex unit 9-3 via the transmission line 21-3 and the reception line 22-3 makes a call to the reception-only facsimile machine 28 to perform facsimile communication. In this case, in the four-wire exchange 1, the terminating side R interface 4 and the terminating side T interface 5 of the line interface section 8-1, and the originating side T interface 3 and the originating side R interface 2 of the line interface section 8-3. They are connected via a third line 29 and a fourth line 30, respectively. Therefore, the data signal output from the facsimile device 27 to the transmission line 21-3 is transmitted through the transmission amplifier 11 → low-pass filter 10 → originating side R interface 2 → fourth 1113130 → receiving side T interface 5 → low-pass filter 15 → Selector switch 16→
The signal is transmitted from the reception amplifier 12 to the reception line 22-1 to the transmission-only facsimile device 23 to the reception-only facsimile device 28.

On the other hand, the response signal output from the reception-only facsimile device 28 is transmitted from the transmission-only facsimile device 23 to the transmission line 2.
1-1 → Transmission amplifier 11 → Selector switch 14 → High frequency filter 13 → Reception side R interface 4 → Third line 29 →
It is transmitted from the originating T interface 3 to the receiving amplifier 12 to the receiving line 22-3 to the facsimile device 27.

Therefore, when transmitting data from the transmission-only facsimile device 23 to the facsimile device 24, the transmission line 2
The low frequency band of the receiving line 22-1 is used for the data signal, and the high frequency band of the receiving line 22-1 is used for receiving the response signal. Further, when receiving data from the facsimile device 27 to the receive-only facsimile device 28, the low frequency band of the receiving line 22-1 is used for data signal reception, and the high frequency band of the transmitting line 21-1 is used for a response signal. In other words, full-duplex communication in different directions is possible between the sending-only facsimile device 23, the receiving-only facsimile device 28, and the facsimile devices 24 and 27.

Next, the transmission line 21-4 and the reception line 11! are connected to the full-duplex unit 9-4. ! A call is made to the reception-only facsimile machine 28 from the facsimile machine 31 connected via the facsimile machine 22-4. In this case, in the four-wire exchange 1, the third line 29 and the fourth line 30 are connected to the terminating side R interface 4 and the terminating side T interface 5 of the line interface section 8-1.
has already been connected, so the line interface section 8-
1, and the calling side T interface 3 and calling side R interface 2 of the line interface section 8-4 are connected via the fifth line 832 and the sixth line 33, respectively. do. At this time, the respective changeover switches 14 and 16 of the full-duplex unit 9-1 are connected to the high-pass filter 13 and the low-pass filter 15, respectively. Therefore, the receiving-side R interface 6 and the receiving-side T interface 7 of the line interface section 8-1 are not connected to the receiving-only fax machine 28, and therefore the facsimile machine @3
1 is in a standby state.

Here, the control section 19 of the full-duplex unit 9-1 controls the facsimile communication between the receive-only facsimile device 28 and the facsimile device 27 based on the signals transmitted via the high-pass filter 13 and the low-pass filter 15. is being monitored. Then, when the control unit 19 determines that the facsimile communication has ended, each of the changeover switches 14 and 1
6 are selectively connected to a high-pass filter 17 and a low-pass filter 18, respectively. At this time, the standby state of the facsimile device 31 is released, and facsimile communication is started between the reception-only facsimile device 28 and the facsimile device 31.

That is, from the facsimile machine 31 to the transmission line 21-4
The data signal outputted to
The signal is transmitted from the transmitting side T interface 7 to the low-pass filter 18 to the selector switch 16 to the reception amplifier 12 to the reception line 22-1 to the transmission-only facsimile device 23 to the reception-only facsimile device 28. On the other hand, the response signal outputted from the reception-only facsimile device 28 is transmitted through the transmission-only facsimile device 23 → transmission line 21-1 → transmission amplifier 11 → selector switch 14 → high-pass filter 17 → called side R interface 6 → fifth line 32 → sending side T interface 3 → receiving amplifier 12 → facsimile machine 31.

In this way, when the facsimile machine 31 makes a call to the receive-only facsimile machine 28 during facsimile communication between the receive-only facsimile machine 28 and the facsimile machine 27, the facsimile machine 31 enters the standby state. When the facsimile communication is completed, the standby state of the facsimile device 31 is released, and facsimile communication is started between the receive-only facsimile device 28 and the facsimile device 31.

C. Effects of the Invention As explained above, according to the present invention, it is possible to perform full-duplex communication in different directions using a general-purpose 4-wire switch, and it is also possible to make other messages to a receiving terminal stand by. possible 4
A standby system for wire switching can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a standby system for a four-wire exchange according to the present invention, and FIG. 2 is a diagram showing frequency characteristics of a transmitting line and a receiving line in opposite direction full-duplex communication. DESCRIPTION OF SYMBOLS 1... 4-wire exchange, 2... Calling side R interface, 3... Calling side T interface, 4, 6... Calling side R interface, 5, 7... Calling side T interface, 8 -1 to 8-4... line interface section,
9-1 to 9-4...Full duplex unit, 10,15°1
8...Low pass filter, 13.17...High pass filter, 11...Transmission amplifier, 12...Reception amplifier, 14
゜16... Selector switch, 19... Control unit, 21-
1 to 21-4... Transmission line, 22-1 to 22-4...
・Receiving line, 23...Facsimile for sending only, 24,
27° 31...Facsimile device, 25...First line, 26...Second line, 28...Reception-only facsimile device, 29...Third line, 30...Third line 4 line,
32...Fifth line, 33...Sixth line.

Claims (1)

[Claims] One line consists of 4 wires, 2 wires on the input side and 2 wires on the output side.
Each line is divided into high and low ranges by filters,
One set of channels or two sets of channels are provided for the input side high range and the output side low range, and two sets of channels or one set of channels are provided for the input side low range and the output side high range, In the standby system of a 4-wire switchboard, in which these three sets of channels per line are exchanged and connected by independent switch groups, the one set of channels is dedicated to outgoing calls, and the two sets of channels are
If a set of channels is designated as incoming calls only, and a call is received on one of the two sets of channels and a call is received on the other set of channels, the incoming call on the other set of channels is waited for. A standby system for a four-wire switchboard is characterized in that the