JPS59219039A - Interface circuit in slave station of radiotelephony equipment - Google Patents

Abstract

PURPOSE:To prevent the malfunction of an off-hook detecting circuit and to eliminate the delay time on off-hook detection by utilizing a ringer signal to control the off-hook detecting circuit. CONSTITUTION:The outputs of a ringer control line 7 from a control circuit 1, an off-hook information transmitting line 8, and an output line of a ringer signal generating circuit 2 are inputted to a gate circuit 12, then it outputs a ringer signal when no off-hook is detected. A ringer signal is transmitted to 2-wire side 9 via an LPF2 and a transformer 4 and also fed to a switch control circuit 11. The circuit 11 turns on a switch 13 for only the positive part of the ringer signal at off-hook, supplies a power supply 5V to a light emitting diode of a photocoupler 14, and turns on normally the switch 13 at off-hook. Since the power supply of the light emitting diode is cut off at the negative part of the ringer signal outputted to the terminal 9, all the power of the circuit 2 is supplied to the telephone set. When the terminal 9 is in off-hook state in response to the call, it is detected by the photocoupler 19, which transmits a detecting signal to the circuit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when an incoming call is received at a self-terminal station, a ringer control signal issued by a control circuit is used to send a ringer signal to two wires to which a SIMI telephone is connected. The present invention relates to an interface circuit in a slave station of a wireless telephone device, which prevents a forward/backward signal from being sent out when an off-hook state of a wireless telephone device is detected and sends the off-hook detection signal to the control circuit.

FIG. 1 shows an interface circuit for detecting off-hook of a handset from ringer generation in a conventional wireless equipment system.

In the figure, 2 is a ringer signal generation circuit, 3 is a low-pass filter (LP'F), and 4 is a transformer.These circuits generate ringer signals (not shown). r,, (2-W of the speaker
It is sent to terminal 9 to which IRE (2 wires) is connected.

5 is a switch, 6 is a delay circuit, and 14 is a photocoupler, and these circuits are circuits for detecting an off-hook state of the telephone.

Reference numeral 1 denotes a control circuit, which activates the ringer signal generation circuit 2 via the control line 7 when it is determined that there is an incoming call to the own terminal station.

It is also a circuit that receives an off-hook detection signal from the off-hook detection circuit section via the off-hook information transmission line 8.

When the control circuit 1 receives a call at its own terminal, it sends the signal shown in FIG. 2(a) to the ringer signal generation circuit 2 through the control line 7. The signal shown in FIG. 1(b) is sent to the 2-Wire.

At this time, since current also flows through the photocoupler 14 in the negative portion (shaded area) of FIG. 2(b), the photocoupler 14 detects an off-hook state even though it is not in an off-hook state.

Conventionally, in order to prevent this, a delay circuit 6 is inserted into the off-hook detection circuit section, thereby preventing the off-hook detection signal from being output to the off-hook information transmission line 8.

However, if such a measure is taken, there is a problem that there is a certain time delay in off-hook detection, during which time the ringer continues to chime.

In addition, in the negative part, current flows through the photocoupler 14 to the ringer signal generation circuit 2, so the load state of the ringer signal generation circuit becomes almost a short circuit state, so the ringer signal supplied to the telephone is only the positive part, and the ringer signal The disadvantage is that the signal power is reduced.

It is an object of the present invention to prevent malfunctions of the off-hook detection circuit and eliminate delay time for off-hook detection by controlling the off-hook detection circuit using a ringer signal, and further to eliminate negative effects of the ringer signal. Another object of the present invention is to provide an interface circuit in a slave station of a radiotelephone device in which a ringer signal is supplied to the telephone set.

In order to achieve the above object, the interface circuit in the slave station of the wireless telephone device according to the present invention has a ringer control signal which is output from the control circuit when there is an incoming call to the own terminal station. In an interface circuit in a slave station of a wireless telephone device, the interface circuit transmits a ringer signal to a telephone line, prevents the ringer signal from being transmitted when an off-hook state of the telephone is detected, and transmits the off-hook detection signal to the control circuit. , a ringer signal generation circuit; a gate circuit that outputs the ringer signal when the incoming call signal from the control circuit is input and the off-hook detection signal is not output; and an unnecessary wave of the output ringer signal. a low-pass filter that removes the
a transformer connected to the line, a photocoupler connected to the two lines and detecting an off-hook state of the telephone, a switch inserted between the photocoupler and the power supply, and detecting the ringer signal when the telephone is on-hook. When the telephone is off-hook, the switch is turned on only when the ringer signal is positive, and the switch is always turned on when the telephone is off-hook.

According to the above configuration, off-hook information without malfunction and delay time can be obtained, and the object of the present invention can be completely achieved.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 3 is a circuit diagram showing one embodiment of the interface circuit according to the present invention.

In the figure, circuit parts using the same symbols as in FIG. 1 are the same circuit parts as those in FIG.

In the circuit section that sends out the ringer signal, the gate circuit 12
uses the ringer control line 7 from the control circuit 1, the off-hook information transmission line 8, and the output line of the ringer signal generation circuit 2 as input lines, and when the signal shown in FIG. 2(a) and off-hook are not detected, the ringer signal Output.

The S/GA signal passes through LpF'3 and transformer 4 to 2-W.
ire, and a part of it is also guided to the switch control circuit 11.

When the switch control circuit n is in the on-hook state (the off-hook information transmission line is at level 7), the switch control circuit n is connected between the light emitting diode side of the photocoupler 14 and the power supply +5V only when the positive part of the ringer signal (Fig. 2 (dotted line part of ω)) is on. Turn on the switch 13 inserted in the.

Further, in the off-hook state (the off-hook information transmission line is at a low level), the switch 13 is always controlled to be in the on state.

Therefore, in the negative part of the ringer signal output to the terminal 9, the power to the light emitting diode of the photocoupler is cut off, so the negative part is also supplied to the telephone.
The full power of the ringer signal generating circuit 2 is supplied to the telephone.

Also, on the off-hook detection circuit side, the photocoupler 14 does not operate depending on the negative part of the ringer signal.When the 2-Wire becomes off-hook in response to this call, the photocoupler 14 detects the positive part of the ringer signal. Since the detection signal is sent directly to the control circuit 1 through the transmission line 8, the off-hook state is immediately detected, and the ringer does not sound after going off-hook.

Once off-hook is detected, the switch control circuit 11 continuously puts the photocoupler 14 into an operable state as described above.

As described in detail above, the present invention enables off-hook information to be detected without malfunction by allowing the off-hook detection circuit to operate only during a part of one cycle of the 16 Hz ringer signal. An interface circuit capable of instantaneous transmission can be realized.

[Brief explanation of the drawing]

1 is a circuit diagram showing an example of a conventional interface circuit, and FIG. 2 is a signal time chart. FIG. 3 is a circuit diagram showing an embodiment of an interface circuit according to the present invention. 1...I! +lI gain 11 circuit 2... Ringer signal generation circuit 3... Low pass filter (LPF) 4... Transformer 5... Switch 6... Delay circuit 7... Ringer control line 8... Off-hook information Transmission line 9...Terminal 11...Switch control circuit 12...Gate circuit 13...Switch 14.
...Photocoupler patent applicant NEC Corporation representative J! 1! Patent attorney Hisashi Inoro-2';

Claims (1)

[Claims] When there is an incoming call at the own terminal station, a ringer control signal issued by a control circuit sends a ringer signal to the two wires to which the telephone is connected, and when an off-hook state of the telephone is detected, the ringer signal is sent. In an interface circuit in a slave station of the radio telephone device, which transmits the off-hook detection signal to the control circuit, a ringer signal generation circuit and a ringer control signal from the control circuit are input, and the off-hook detection signal is transmitted to the control circuit. a gate circuit that outputs the ringer signal when no signal is output; a low-pass filter that removes unnecessary waves from the output ringer signal; and a gate circuit that is connected to the two wires to which the ringer signal from the low-pass filter is input. a transformer connected to the two wires, a photocoupler for detecting an off-hook state of the telephone, a switch inserted between the photocoupler and the power supply; An interface circuit in a slave station of a wireless telephone device, comprising a switch control circuit that turns on the switch only when a ringer signal is positive and always turns on the switch when the telephone is in an off-hook state.