JPS62128254A - Transmission system for control signal in counter communication system - Google Patents

Abstract

PURPOSE:To keep excellent communication quality and to simplify the constitution by sending a control signal from a transmission terminal equipment to a reception side counter communication equipment and applying communication when the return of a ring back tone is stopped so as to utilize no superimposition of a control signal on a communication signal. CONSTITUTION:When a handset of a four-wire telephone set 100 is lifted up, a signal is inputted to a hook-off detection circuit 10 of a counter communication equipment 1 at the reception side, a decision circuit 16 gives a control command to a control signal generating circuit 13 based on the detected output to send the control signal to a line L via an amplifier 17 and a hybrid transformer 19. On the other hand, a counter communication equipment 2 being the reception side uses a decision circuit 26 to give a control command to a call signal generating circuit 25 and an RBT generation circuit 24 based on the detection output of a control signal detection circuit 21 to call a telephone set 200, and the RBT generated from the RBT generation circuit 24 is returned to the said counter communication equipment 1 at the transmission side via an amplifier 27, a hybrid transformer 29 and the line L.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides control of terminals such as telephones or facsimile machines that correspond to each communication device on a one-to-one basis through communication devices that are connected oppositely to a line. The present invention relates to a method for transmitting control signals in a two-way communication system.

[Technical background of the invention]

As is well known, a so-called two-way communication system is a communication system in which communication is performed between terminals such as telephones or facsimile machines that correspond one-to-one to each communication device through communication devices that are connected oppositely to a line. Although this is one of the simplest configurations, the minimum requirement is a configuration that can control operations such as starting, maintaining startup, and restoring the above-mentioned terminal during the above-mentioned communication. Normally, such operation control is performed by sending a corresponding control signal from the sending-side opposing communication device to the receiving-side opposing communication device among the communication devices connected oppositely to the line. There have been three typical methods for transmitting control signals in this type of conventional two-way communication system as shown below.

(2) DC signal transmission method DC control signals are used to control the activation, activation maintenance, recovery, etc. of the receiving terminal, and AC signals are used for communication.

■8 Signal transmission method during a call A frequency not used for communication within the band is applied to the control signal, the control signal sent during communication is separated from the signal for communication by a filter, and the receiving terminal is activated. Controls startup maintenance, recovery, etc.

(2) No-call signal transmission method A control signal is applied to a specific frequency, and the control signal sent when no communication is being performed controls the activation, activation maintenance, recovery, etc. of the receiving terminal.

(Problems of the Background Art) However, according to the conventional two-way communication system described above, each method has the following problems.

a. The DC signal transmission method is the easiest method to implement, but it cannot be applied to lines that do not pass DC.

The B8 call signal transmission method requires a filter to separate the control signal from the communication signal, which complicates the configuration and increases costs.It is also difficult to completely separate the control signal, resulting in poor communication quality. descend.

The C0 no-call signal transmission method maintains good communication quality because the control signal is not superimposed on the communication signal, but when the spectrum of the communication signal approaches the control signal, it is misidentified as a control signal and the control as described above occurs. When an operation is executed or when the opposing communication device on one side is powered off, a malfunction occurs, such as calling a terminal connected to the opposing communication device on the opposite side.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and can be used in circuits that do not pass direct current, and can maintain good communication quality with a simple configuration, and can also contribute to preventing malfunctions. The purpose of the present invention is to provide a control signal sending method in a two-way communication system.

[Summary of the invention]

Therefore, in the present invention, communication between an off-hook detection circuit that detects off-hook of a corresponding terminal, and a receiving side that calls the corresponding terminal based on a control signal sent based on the detection output of the off-hook detection circuit when the terminal goes off-hook. a ringback tone detection circuit that detects a ringback tone that is continuously returned from the device until the terminal responds to the call; and a ringback tone detection circuit that detects the ringback tone when the ringback tone is no longer obtained. The above object is achieved by providing each of the communication devices with a determination circuit that stops sending out the control signal based on the detection output of the communication device.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of the two-way communication system according to the present invention when a four-wire telephone is used as a communication terminal, and the two-way communication devices 1 and 2 connected oppositely to the line are: They have the same configuration, respectively, hook-off detection circuits 10 and 20, control signal detection circuits 11 and 21, ringback tone (hereinafter abbreviated as RBT) detection circuits 12 and 22, and control signal generation circuits 13 and 23.
, R, B T generation circuits 14 and 24, calling signal generation circuits 15 and 25, determination circuits 16 and 26, amplifiers 17.18 and 27.28, hybrid transformer 1
It consists of 9 and 29. Further, the opposing communication device 1
and 2 are connected to the four-wire telephone 1 as the communication terminal through hook-off detection circuits 10 and 20 and ringing signal generation circuits 15 and 25, respectively, on the opposite side of the line.
00 and 200.

Hereinafter, the control operation in this two-way communication system when the 4-wire telephone 100 is used as a transmitting terminal and the 4-wire telephone 200 is used as a receiving terminal will be described below with reference to the communication control procedure shown in FIG. I will explain in detail.

First, the 4-wire telephone (hereinafter referred to as telephone) 10
0, when the handset is lifted up, a signal indicating the state of the hook switch at this time is input to the 7-touch-off detection circuit 10 of the opposing communication device 1 serving as the receiving side.
A hook-off is detected. Based on the detection output of the hook-off detection circuit 10 at this time, the determination circuit 16:
A control command is given to the control signal generation circuit 13, and the control signal generated from the control signal generation circuit 13 is transmitted to the amplifier 17,
The signal is sent to the line via the hybrid transformer 19.

On the other hand, the opposing communication device 2 serving as the receiving side receives the control signal input from the line [through the hybrid transformer 2].
9 to the control signal detection circuit 21, where the control signal is detected. Based on the detection output of the control signal detection circuit 21 at this time, the determination circuit 26 gives a control command to the ringing signal generation circuit 25 and the RBT generation circuit 24, and transmits the ringing signal generated from the ringing signal generation circuit 25 to the telephone. 11200 to make a call, and
The RBT generated from the RBT generation circuit 24 is returned to the opposing communication device 1 on the transmitting side via an amplifier 27, a hybrid transformer 29, and a line.

In the opposing communication device 1, the RBT is guided from the line through the hybrid transformer 19 to the RBT detection circuit 12 and detected. Then, the determination circuit 16 determines that the R
While the RBT is detected by the BT detection circuit 12, the control signal generation circuit 13 is controlled so that the control signal is continuously sent to the opposing communication device 1 on the receiving side.

Now, in the opposing communication device 2 on the receiving side, the determination circuit 26
In response to the above call made by the telephone tf
When the handset of the i200 is lifted, a signal indicating the state of the hook switch at this time is input to the 7-touch-off detection circuit 20, and hook-off is detected. Based on the detection output of the hook-off detection circuit 20 at this time, the determination circuit 26 gives corresponding control commands to the call signal generation circuit 25 and RBT generation circuit 24, and stops sending out the call signal and RBT. . According to the control of the opposite communication device 2 on the receiving side, the RBT detection circuit 12 of the opposite communication device 1 on the transmitting side detects the RB
T is no longer detected.

Based on the detection output of the RBT detection circuit 12 at this time, the determination circuit gives a control command to the control signal generation circuit 13 to stop sending out the control signal as described above. From then on, the telephone 100 that requested the call,
Communication (call) is carried out through the line with the telephone 200 that responded to the call. Furthermore, both these telephones 110
Restoration of the 0°200 operation will be achieved by hooking on both parties at the end of the call.

In this embodiment, only a configuration example in which a telephone is used as the communication terminal has been described, but it goes without saying that other communication terminals such as a facsimile device can also be used.

〔Effect of the invention〕

As explained above, according to the control signal sending method in the opposing communication system of the present invention, based on a communication request from the sending terminal, a control signal is sent from the opposing communication device on the sending side to the opposing communication device on the receiving side. , the transmission of the control signal is stopped at the time when the receiving terminal responds to the communication request and the sending of the ringback tone from the receiving side's opposing communication device to the receiving side's opposing communication device is stopped, and thereafter, Since communication is carried out, A. It can also be applied to lines that do not pass direct current.

Since the control signal is not included in the B0 communication signal, good communication quality can be maintained, and since there is no need for a filter or the like to separate the communication signal and the control signal, the configuration can be simplified.

It is possible to prevent malfunctions such as a C0 communication signal being misrecognized as a control signal and a control operation being executed, or a terminal connected to the opposing communication device on the opposite side being called when the opposing communication device on one side is powered off. .

It has the excellent advantages of a hat.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a two-way communication system according to the present invention, and FIG. 2 is a diagram showing an example of a communication control procedure in the two-way communication system shown in FIG. 1.2... Opposite communication device, 10.20... Hook-off detection circuit, 11.21... Control signal detection circuit, 12
．． 22...Ringback tone (RBT) detection circuit,
13.23... Control signal generation circuit, 14.24...
RBT detection circuit, 15.25... Calling signal generation circuit, 16.26... Judgment circuit, 17.18, 27.28
...Amplifier, 19.29...Hybrid transformer, 100.200...4-wire telephone, and...Line.

Claims (1)

[Scope of Claims] A control signal sending method in a two-way communication system for controlling a terminal corresponding to each communication device on a one-to-one basis through communication devices that are connected oppositely to a line, comprising: is an off-hook detection circuit that detects off-hook of a corresponding terminal, and a communication device on the receiving side that calls the corresponding terminal based on a control signal sent based on the detection output of the off-hook detection circuit when the terminal goes off-hook. a ringback tone detection circuit that detects a ringback tone that is continuously returned until the terminal responds to the call; and a detection output of the ringback tone detection circuit when the ringback tone is no longer obtained. 1. A system for transmitting control signals in a two-way communication system, characterized in that each of the systems is provided with a determination circuit that stops transmitting the control signal based on the timing of the transmission of the control signal.