JPH0767131B2 - Network control circuit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network control circuit for connecting a facsimile machine having a communication function to a line.

2. Description of the Related Art A conventional network control circuit has a configuration as shown in FIG. 2, in which a CML relay 104 is opened during standby, and a line is a telephone set, a subscriber telephone network incoming call detecting means 106 and a facsimile communication network incoming call detection. CML is connected to each of the means 107, but when the incoming telephone network incoming call detecting means 106 or the facsimile communication network incoming call detecting means 107 detects an incoming call from the network.
The relay 104 is closed so that the telephone, the incoming telephone network incoming call detecting means 106 and the facsimile communication network incoming call detecting means are disconnected from the line. When the CML relay 104 is closed, 105 forms a DC circuit of the line, and is connected to the facsimile machine via the hybrid coil 110 for 2-wire / 4-wire conversion from both ends thereof by AC coupling with a capacitor. In the case of automatic calling, it is necessary to prevent a collision with an incoming call. For this purpose, first the L relay 101 is closed and the photocoupler 102 is closed.
After confirming that there is no polarity reversal of the line before the incoming call for a certain period of time by the output 103 of, the CML relay 104 is closed and the P relay 10
8 is turned on / off according to the other party's number to transmit the pulse dial signal to the network. When the transmission of all digits of the dial number is completed, the polarity reversal detection circuit 109 confirms the other party's response, and the CML relay 104 is closed to carry out the facsimile communication with the line being captured. The divider 11
1 is in the closed state in the normal case other than the test or maintenance inspection. The subscriber telephone network incoming detection means 106 and the line are coupled by a photocoupler AC-coupled by a capacitor, and the facsimile communication network incoming detection means 107 and the line are coupled by a transformer AC-coupled by a capacitor. . The telephone is connected to the line when the sill is open for testing or servicing, and when the CML relay 104 is open during standby or for control calls. Hybrid circuit inside the phone 11
It has a built-in 2-wire to 4-wire conversion circuit similar to 0, and is connected to the transmitter, the receiver, and the line.

Problems to be Solved by the Invention Such a conventional network control circuit includes a CML relay for switching a signal path from a line, a relay for performing an incoming / outgoing collision prevention operation, a P relay for transmitting a dial pulse, and the like. Increasing the size of the relay because it has a plurality of relays and a plurality of coils such as a letter coil and a hybrid coil for connecting the DC circuit of the line, and a coupling coil having a high input impedance for connecting to the facsimile communication network incoming detection circuit. It has the disadvantage that it cannot escape. That is, to explain this in more detail, in order to withstand a DC current of about 100 mA and a DC voltage of about 48 V on the line and to prevent magnetic saturation and impedance matching, thicken the winding of the hybrid coil or letter coil, and along with this It is practically difficult to reduce the size of these hybrid coils and letter coils because the magnetic material must be large. Again 2
When connecting a line-balanced line with an unbalanced incoming detection circuit, the incoming telephone network (16H
In z), it is possible to reduce the size by applying a photo coupler, but in the facsimile communication network (1300Hz) where the incoming signal level is low, the photo coupler cannot be used, and there is no choice but to use transformer coupling. For CML relays for signal path switching, downsizing was not possible from the viewpoint of contact reliability and contact material economy.

Furthermore, in the conventional network control circuit, even in the case of facsimile communication, the attached telephone will ring a ringing tone for a moment without fail when an incoming call is received from the subscriber telephone network, thereby generating unnecessary noise. This is because the telephone is connected in parallel with the incoming call detection circuit during standby, and the bell of the telephone will ring during the time it takes to complete the incoming call detection and switch the CML relay. In addition, since it has two hybrid circuits including the inside of the telephone, it has a drawback of complicating the circuit.

The present invention solves the above-mentioned disadvantages of the prior art, and has conventionally required a letter coil for closing a DC circuit, a hybrid coil for 2-wire to 4-wire conversion, and an incoming call of a facsimile communication network. The coupling coil that connects the detection circuit and the line is omitted to improve the linearity of the characteristic impedance seen from the line, and various relays for signal path switching are also omitted to make the circuit compact and highly reliable. An object of the present invention is to provide a network control circuit which realizes economic efficiency and which does not cause a telephone to ring a bell when a facsimile automatic reception is started in a subscriber telephone network.

Means for Solving the Problems To achieve the above-mentioned object, the network control circuit according to the present invention includes first detecting means for detecting the polarity reversal of the line, and the first detecting means.
Second detecting means for detecting the arrival of a facsimile signal based on the detection from the detecting means, and when the facsimile signal is detected by the second detecting means, the facsimile communication is performed without ringing the ringing tone of the telephone. When the facsimile signal is not detected by the second detecting means, the control means causes the ringing tone of the telephone to ring and shift to the talking state.

Operation With the above-described configuration, the present invention can prevent the telephone bell from sounding at the start of automatic facsimile reception, and can shift the telephone call state by generating the telephone bell tones during a call.

EXAMPLE A network control circuit according to an embodiment of the present invention will be described below in detail with reference to FIG. 1. Reference numeral 201 denotes a line for disconnecting a line from a facsimile and directly connecting to a test telephone at the time of test or maintenance. It is a divider and is composed of a slide switch, but normally this test telephone is unnecessary and the divider 20
Leave 1 closed. Reference numeral 202 is a rectifier circuit composed of a diode bridge, which converts the signal form from a balanced type to an unbalanced type while keeping the polarity state of the line in one.
Reference numeral 203 denotes a modem transmitting section, a single tone transmitting section, a telephone transmitter section, a tone dial section, a voice response section, etc. of the facsimile main body 212 via a hybrid circuit 226, an analog switch 218 and a capacitor 217 according to a control procedure. It is a multiplexer for controlling transmission to the line. Reference numerals 204 and 205 divide the direct current of the line into a photocoupler 20.
A resistor for energizing the light-emitting diodes that make up the 8, 206
Is a varistor for overvoltage protection, 207 is an AC signal bypass capacitor, and 209 is a constant voltage diode for overvoltage protection. The photocoupler 208 is composed of a pair of light emitting diodes and transistors which are connected in parallel in opposite directions in order to detect the polarity reversal of the line. Reference numeral 210 is a transistor that controls a weak current that enables one of the light emitting diodes of the photocoupler 208 to be turned on without capturing a line prior to automatic call origination, and 211 is a resistor that determines this current value. . The facsimile main body 212 controls the network control circuit of the present invention based on the communication procedure. 213 and 214 are Darlington-connected transistors for capturing the line during communication and for turning on / off the pulse dial signal transmission, and the resistor 227 determines the current value when capturing this line. 215 is a field effect transistor FET
The MOS (Metal Oxside Semico) is a resistor that supplies a minute current from the line to its gate to turn on the 216 during standby.
The nductor) type FET 216 maintains the ON state from the standby state to the end of the incoming call detection by the function of the resistor 215. Reference numeral 217 is a capacitor for AC coupling, and 218 is an analog switch circuit for controlling opening / closing of this AC signal with the hybrid circuit 226, which is turned off and has high impedance except during communication. Reference numeral 219 is a buffer FET for guiding the ringing signal from the network to the incoming detection means 222 by high impedance coupling that does not affect the line, 220 is a resistor that determines this high input impedance, and 221 is a capacitor for AC coupling. is there. The incoming call detecting means 222 integrates the frequency or cycle of the input signal and automatically distinguishes between the bell ringing signal of 16 Hz of the subscriber telephone network and the ringing ringing signal of 1300 Hz of the facsimile network. 223 is F
The input resistors 224 and 225 of the ET219 are clamp diodes for protecting the gate input of the FET219.

226 is a two-wire / four-wire conversion hybrid circuit composed of a differential amplifier and a resistor, and has a line characteristic impedance of 600
Ω coupled to analog switch 218. 227 is a resistor connected to the emitter of the transistor 214. 228 is a hybrid circuit 22 for the receiving circuit of the modem receiving unit, the single tone detecting unit or the telephone receiver of the facsimile main body 212.
It is a demultiplexer for selecting and guiding the received signal from 6 according to the control procedure.

Next, the operation of the network control circuit configured as described above will be described. In the standby state, only the FET 216 is on and the line is connected only to the incoming call detecting means 222. At the time of automatic dialing, the FET 216 is turned off and the transistor 210 is turned on for about 300 milliseconds (hereinafter referred to as T ₁ ), and during this period, the photocoupler 208 detects the presence or absence of polarity reversal and prevents the incoming and outgoing collision. When the photocoupler 208 detects polarity reversal during T _1, an incoming signal is sent from the network, so that the transistor 210 is turned off, the FET 216 is turned on, and the FET 216 is turned off after the incoming detection means 222 detects an incoming call. The transistors 213, 214 and the analog switch 218 are turned on to form a DC circuit, and a hybrid circuit is formed.
The AC signal is guided to the facsimile main body 212 via the multiplexer 226, the multiplexer 203 or the demultiplexer 228 so that the facsimile can be communicated. The automatic incoming call operation from the standby state is performed in exactly the same manner as the above except that the outgoing / incoming call collision prevention operation before the automatic outgoing call is not performed. Transistor 210
When polarity reversal is not detected within the on-state T _{1 of}
Transistors 213 and 2 with transistor 210 turned off
14 is turned on / off according to the dial number and a dial pulse is sent to the network. When tone dialing is performed without using pulse dialing, the transistors 213 and 214 are turned on, and a dial signal is sent from the tone dialing unit of the facsimile main body 212 to the network via the multiplexer 203 and the hybrid circuit 226. When the dialing of all digits is completed in this way, the transistors 213 and 214 are turned on, the connection response is confirmed by the photo coupler 208 by polarity reversal, and then the analog switch 218 is turned on to form a signal path for facsimile communication via the hybrid circuit 226. .

When the photocoupler 208 does not detect polarity reversal as a connection response confirmation from the network at the end of dialing, or when an interruption instruction from the network is detected as polarity reversal during facsimile communication, the facsimile returns to the standby state. To do.

During a call, the transmitter of the telephone of the facsimile main body 212 is connected to the hybrid circuit 226 via the multiplexer 203 and the receiver to the demultiplexer 228. In this call state, the signal path is formed by the operation button instruction of the facsimile main body 212 or the incoming call detection means 222 detects the incoming call from the subscriber telephone network, and the single tone part, the voice response part and the modem of the facsimile main body 212 are detected. This is the case where a facsimile signal is not detected within a certain period of time after responding at the receiving unit, at which time the telephone rings the ringing tone for the first time.

The semiconductor switch circuit or the analog switch in the network control circuit according to the present invention is not limited to the configuration of the embodiment shown in FIG. 2, and is constituted by a photocoupler in consideration of insulation between the signal path and the switching control signal. May be.

The switching element may be a FET or bipolar transistor, and a thyristor may be used.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the first detecting means for detecting the calling signal from the calling side after the detection of the polarity reversal of the line and the output from the first detecting means are provided. In response to the second detection means, the second detection means starts detecting the arrival of the facsimile signal, and when the second detection means detects the facsimile signal, the telephone call is not made and the facsimile communication is immediately started to perform the second detection. When the means does not detect the facsimile signal for a certain period of time, it is equipped with a control means that causes the facsimile device to emit a ringing tone indicating a call request and shifts to the call state. It is possible to prevent the telephone from making a ringing tone when receiving a call from the network, and at the time of a telephone call, the alarm tone generator of the fax machine body generates a ringing tone indicating a call request. Therefore, it is possible to contribute to the prevention of noise, and it is possible to further improve the miniaturization and economy of the circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a network control circuit according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional network control circuit. 201 …… Slide switch, 202 …… Rectifier circuit, 203 ……
Multiplexer, 216,219 …… FET, 206 …… varistor, 2
08 …… Photo coupler, 209 …… Constant voltage diode, 218…
… Analog switch, 212… Facsimile body, 222…
… Incoming call detection means, 223,225 …… Clamp diode, 226
…… Hybrid circuit, 228 …… Demultiplexer.

Front page continuation (72) Inventor Takushi Iga 2-3-8 Shimomeguro, Meguro-ku, Tokyo Matsushita Densen Co., Ltd. (72) Inventor Takahiro Kikuchi 2-3-8 Shimeguro, Meguro-ku, Tokyo Matsushita Dentsu Inc. (72) Inventor Toshio Narushima 2-3-8 Shimomeguro, Meguro-ku, Tokyo Matsushita Dentsu Inc. (72) Hiroaki Nouchi 2-3-8 Shimeguro, Meguro-ku, Tokyo Matsushita Dentsu Co., Ltd. In-house (56) References JP 55-138963 (JP, A) JP 59-128868 (JP, A)

Claims (1)

[Claims] 1. A first detecting means for detecting a calling signal from a calling side after detecting a polarity reversal of a line, and the detection of an incoming facsimile signal according to an output from the first detecting means. When the second detecting means and the second detecting means detect a facsimile signal, the facsimile communication is immediately started without calling a call, and the second detecting means does not detect the facsimile signal for a predetermined time. in case of,
A network control circuit comprising: a control unit that causes a facsimile device to emit a ringing tone indicating a call request to shift to a call state.