JPS61161865A - Network controlling circuit - Google Patents

Abstract

PURPOSE:To miniaturize a circuit by constituting a switching circuit to switch the connection of telephone or facsimile with semiconductor elements. CONSTITUTION:In case of automatic dialing, an FET216 is made off, and a transistor (TR)210 is turned on during approximately 300ms, in such a period, the polarity inversion is detected by a photocoupler 208 to search the arrival of signal so that collision is prevented. If the polarity inversion is detected, a call signal is transferred from the net by which the TR210 is turned off but the FET216 is on. Also, the FET216 is turned off after the signal-arrival is detected by an arrival detecting mean 222, while a TR213 and an analogue switch 218 are turned on, and accordingly a D.C. circuit is formed. At the same time, an A.C. signal is lead to a facsimile main body 212. The operation of switching to automatic receiving from the waiting status is performed completely likewise. On the other hand, if the polarity inversion is not detected, a dial-form pulse is transmitted to the network by ON/OFF controlling the TR213.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a network control circuit for connecting a facsimile machine to a line, and more particularly to a network control circuit that is small and simple in structure and capable of detecting polarity reversal.

Conventional technology FIG. 2 shows a schematic configuration of a conventional network control circuit.

FIG. 2 shows a facsimile incoming call standby state. 7
-P facsimile is connected to the subscriber telephone network and the line of the facsimile communication network via disconnector 111, CML relay 104, and P relay 1 for generating pulse signals.

This connection circuit includes subscriber telephone network incoming call detection means 10 in parallel.
6. The facsimile communication network incoming call detection means 107 and the photocoupler 102 are connected in series to the polarity reversal detection circuit 10.
9 is connected. A telephone set 112 is attached to the facsimile machine, and a disconnector 111 is used to switch to either the above connection circuit or the parallel circuit of subscriber telephone network incoming call detection means 106.7 axis communication network incoming call detection means 107 and Otokagura 102. It is connected to the.

A letter coil 1 is connected downstream of the relay 108 so that when the CMLIJ relay 104 is closed, the line forms a DC circuit.
05 is provided.

The subscriber telephone network incoming call detection means 106 includes a photocoupler 106a that receives an incoming call signal from the telephone network and this photocoupler 10.
Telephone detection circuit 10 detects an incoming call based on the output signal of 6a.
6b.

The facsimile communication network incoming call detection means 107 is a high impedance transformer 107a that receives an incoming facsimile signal.
and a facsimile detection circuit 107b that detects incoming facsimile calls based on the output of the transformer 107a.

When an incoming call is detected by the facsimile communication network incoming call detecting means 107, the subscriber telephone network incoming call detection means 106 or 9 sends a CM
The L relay 104 is closed, and the telephone set 112 subscriber telephone network incoming call detection means 106 and facsimile communication network incoming call detection means 1
07 is disconnected from the line, and at the same time the letter coil 105
The line and facsimile are AC coupled by nine capacitors installed at both ends of the line.

In the network control circuit having such a configuration, when the line is disconnected, the CMLIJ relay 104 is in the open state, and the line is connected to the telephone set, subscriber telephone network incoming call detection means 106, and facsimile communication network incoming call detection means 107, respectively. However, when the subscriber telephone network incoming call detecting means 106 or the facsimile communication network incoming call detecting means 107 detects the incoming call from the network, the CML relay 104 is closed, and the telephone, the subscriber telephone network incoming call detecting means 106 and the facsimile communication network The incoming call detection means 107 is disconnected from the line.

When the CML relay 104 is closed, the letter coil 105 forms a direct current circuit of the line, and is connected to the facsimile machine through alternating current coupling via a capacitor from both ends thereof.

In the case of automatic call origination, it is necessary to prevent collision with an incoming call, and for this purpose, the L relay 101 is first closed for milliseconds, and the polarity of the line is reversed before the incoming call by the output 103 of the 7-oto coupler 102. Confirm that there is no CML for the above several hundred milliseconds and perform CML 1. Lu-104i closed, letter coil 1
05 to form a DC loop, and the letter coil 1o6.
The subscriber telephone network incoming call detection means 106 and the facsimile communication network incoming call detection means 107 are opened by the CML relay 104, and the P relay 108 is turned on and off according to the called party's number to transmit a pulse dial signal to the network. has been done. When the transmission of all digits of the dial number is completed, the polarity reversal detection circuit 109 detects the polarity reversal caused by the connection confirmation with the network or the other party's terminal or the communication interruption command from the network, and closes the CML relay 104 to disconnect the line. Perform facsimile communication in the captured state.

When a call arrives, the subscriber telephone network incoming call detection means 106 detects a calling signal from the subscriber telephone network, and the facsimile communication network incoming call detecting means 107 detects a calling signal from the facsimile communication network. When this incoming call is detected, the CML relay 104 is closed and the connection to the line is controlled by capturing the circuit. During the transmission/reception operation, the CMLIJ relay 104 is closed and maintains the following state.

When the communication is interrupted or terminated, the CMIIJ relay 104i is opened and disconnected, and the line is connected to the telephone set 106 and the incoming call detection means 106 and 107.

The disconnector uses a slide switch to disconnect the facsimile and network control and directly connect the line and telephone for maintenance or testing purposes. In some cases, it is in a closed state. The subscriber telephone network incoming call detection means 106 is coupled to the line by a photocoupler 102, which is AC-coupled by a capacitor, and the facsimile communication attachment detection means 107 is coupled to the line by a transformer, which is AC-coupled by a capacitor. There is.

Problems to be Solved by the Invention Such a conventional network control circuit includes a friend CML relay 104 for switching the signal path from the line, a relay 101 for performing call/receive collision operations, and a ninth P for dial pulse transmission.
The network has a plurality of relays such as a relay, and a plurality of coils such as a coupling coil having a high input impedance that connects with the letter coil 105, 7 axis communication network layer signal detection circuit for connecting the DC circuit of the line. This has the disadvantage that the control circuit itself has to be structurally enlarged.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to configure a circuit for switching connections between telephones or facsimile machines using conductor elements instead of coils and relays, and to control a network control device. and to solve the above-mentioned conventional problems.

Means for Solving the Problems The present invention achieves the above object by using a conductor switch circuit instead of a relay in switching the signal path in the network control circuit, and also by forming a direct current circuit of the line and reversing the polarity. Detection and control are also performed by a conductor switch circuit, and a circuit for detecting polarity reversal or hook-off consisting of two photocouplers is installed on the input side of the rectifier circuit that converts and maintains the line polarity constant. is arranged in series with a rectifier circuit, and the above-mentioned conductor switch circuit is arranged in series on the output side of the rectifier circuit.

Function As described above, the present invention can be miniaturized by replacing the ninth relay circuit that switches the signal path from the line and the letter coil for connecting the direct current circuit of the line, which are obstacles to miniaturization, with a semiconductor switch circuit. becomes possible.

Practical Example Below, the details of the network control circuit according to an embodiment of the present invention will be explained with reference to FIG. It consists of a slide switch, which is normally in the closed state. 202 is a rectifier circuit composed of a diode bridge circuit, and even if the polarity state of the line is either earth or negative, it converts it to direct current while maintaining that state.

In the present invention, a first conductor switch circuit S1 consisting of a resistor 211 and a transistor 210 and a second conductor switch circuit S1 consisting of a resistor 214 and a transistor 213 are connected to the output of the rectifier circuit 202. A conductor switch circuit S3 is connected thereto. 204 and 205 are predetermined resistors that shunt the direct current of the line and supply current to a polarity reversal detection circuit constituted by a photocoupler 208. Photo coupler 20
Reference numeral 8 is composed of two light emitting diodes and a transistor connected in parallel in opposite directions to each other in order to detect polarity reversal of the line. 206 is a varistor for overvoltage protection. 209 is a Zener diode connected to the positive side of the output of the rectifier circuit 202 and set to about 60 volts for overvoltage protection.

The transistor 210 constituting the first conductor switch circuit S1 becomes conductive when a control signal from the facsimile main body 212 is applied to its base, and is limited by a resistor 211 to control the constant current on and off. However, this transistor 210 controls a weak current that enables one of the light emitting diodes of the 7-otokagura 208 to be lit without seizing the line prior to an automatic dialing (ie, calling) operation.

Then, the photocoupler 208 detects the presence or absence of polarity reversal, and the transistor 210 is turned on to prevent collision with an incoming call.

The transistor 213Fi that constitutes the 20th hand conductor switch circuit turns on and off in response to the destination number when pulse dialing is sent.The transistor 213Fi captures the line during communication, and the resistor 214 controls this line. Determine the current to capture. 2
A resistor 16 biases the gate of the transistor 218 with a rectified positive voltage from the line, and a resistor 216 connects the line to the telephone 203 and the incoming call detecting means 222 with the resistor 216 normally in an on state. It is a high voltage enhancement type MO8FET. 217 is a ninth capacitor that couples only the AC signal component between the line and the facsimile body 212t; 218 is an analog conductor switch circuit for controlling the input/output of the facsimile AC signal to the line; 219 is an incoming call detection means 2 for receiving a call signal from the network.
22 is a buffer FET with high input impedance, and 220 is a load resistance that determines the input impedance. 221 is a capacitor for guiding only the calling signal from the network to the incoming call detection means 222 by AC coupling, and 222 is a capacitor for detecting the calling signal from the network, 1e Hz from the subscriber telephone network and 1300 Hz from the facsimile communication network.
This is an incoming call detection means that performs detailed classification of calls. 223 is FET
219 input resistance, 224 and 2226 are FET219
This is a clamp diode for input protection. Reference numeral 212 denotes a facsimile main body, which controls on/off of the conductor switch circuit of the network control circuit according to the present invention based on a communication procedure, and also transmits and receives AC signals.

Next, the operation of the friend network control circuit configured as described above will be explained. In the hold state, only FET 216 is on. When performing automatic dialing, the FET 216Q is turned off and the transistor 210 is turned on for approximately 300 milliseconds. During this time, the photocoupler 208 detects polarity reversal, checks whether there is an incoming call, and performs an operation to prevent collision with an incoming call.

When polarity reversal is detected, the network sends a call signal, which turns off transistor 210 and turns off FET
216'i is turned on, the incoming call detection means 222 detects the incoming call, and then the FET 21e is turned off, and the transistor 213 and analog switch 218 are turned on to form a DC circuit and an AC signal is guided to the facsimile body 212, and the facsimile is Communication becomes possible and reception begins.

When the communication ends, the facsimile returns to the suspended state.

The operation of automatic reception from a standstill state when there is no automatic calling operation is performed in exactly the same manner as described above. If no polarity reversal is detected during the on-state of transistor 210 for approximately 300 milliseconds, dial pulses are sent to the network by controlling transistor 2130 to turn on and off while transistor 210 is off. When the transmission of dial pulses for all digits is completed, the transistor 213ft is turned on, and the connection response is confirmed by reversing the polarity using the 7-point controller 208 in a steady state, and the analog switch 218 is turned on to generate an AC signal that enables 7-ac 7-mm communication. Create a route. Mayu,
Even when performing tone dialing instead of pulse dialing,
A dial tone is sent from the facsimile body 212 via the analog switch 218 with the transistor 213 turned on and the times St- captured. The operation after the completion of sending all digits is the same as in the case of the pulse dial described above.

7 When the Oto coupler 208 does not detect a polarity reversal as a connection response confirmation from the network at the end of dialing, or when an interrupt instruction from the network is detected as a polarity reversal during facsimile communication, the facsimile is suspended. to return to.

Although one embodiment of the present invention has been described above, the structure of the semiconductor switch circuit is not limited to the transistors shown in FIG. 2, and either FET or bipolar transistors may be formed by thyristors.

Effects of the Invention According to the present invention, which will be described in detail above, both the relay circuit for switching the signal path of the line and the letter coil for forming the DC circuit, which were conventionally considered indispensable in the network control circuit, are made of semiconductors. Since it is replaced by a switch, the circuit can be made smaller, more reliable, and more economical.

In addition, there is no dedicated polarity reversal detection circuit that prevents calls from colliding with each other before the automatic call operation, and by controlling a semiconductor switch circuit that controls a minute current, communication is still in progress by the time the call ends. Since it can be shared with the polarity reversal detection circuit for detecting interruptions in the system to detect polarity reversal before the arrival of the call signal, it is possible to reduce the circuit size, maintain reliability, and make it more compact and economical. It has the effect of Furthermore, since there are no relays or coils, the network control circuit can be integrated into an integrated circuit using these semiconductor elements, resistors, and capacitors to reduce the size and improve reliability. Note that hook-off of the telephone can also be detected using this polarity reversal detection circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a network control circuit showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional network control circuit. 201...Disconnector, 202-...Rectifier circuit, 2o3...Telephone, 208-...Photocoupler, 216°219...FET, 206
...Harris, Ri, 209... Constant voltage diode, 21o... Transistor, 211.
...Resistor, 213...Transistor, 2
14... Resistor, 218... Analog switch, 212... Facsimile body, 223
,225... Clamp diode. Name of agent: Patent attorney Toshio Nakao and 1 other person 2e
I... Ren σ+8 zt#--Analog switch 20θ...Photocuff...

Claims (1)

[Claims] A rectifier circuit that converts and maintains the line polarity constant, two light emitting diodes placed in series with the input of this rectifier circuit and connected in parallel in opposite directions, and monitoring the lighting status of these light emitting diodes. and a means for detecting polarity reversal of the line, connected in parallel with the output of the rectifier circuit as the means for detecting polarity reversal of the line,
and a first semiconductor switch that controls a minute current that causes the light emitting diode to light up in a state where the line is not captured;
a second semiconductor switch circuit that captures a line to make a call or answer a call and controls a minute current that causes the light emitting diode to light up;