JPH0315873B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a ringer control signal that is generated by a control circuit when a call is received at a terminal station, and sends a ringer signal to two wires to which a telephone is connected. The present invention relates to an interface circuit in a slave station of a radio telephone device that prevents the ringer signal from being sent out when a state 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 generation of ringing in a conventional wireless equipment system.

In the figure, 2 is a ringer signal generation circuit, 3 is a low-pass filter (LPF), and 4 is a transformer.
These circuits send ringer signals to a terminal 9 to which a 2-Wire (two wire) of a telephone (not shown) is connected.

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

Reference numeral 1 denotes a control circuit, which activates the ringer signal generation circuit 2 via a control line 7 when it is determined that a call has arrived at the own terminal station. It is also a circuit that receives an off-hook detection signal from an off-hook detection circuit section via an off-hook information transmission line 8.

FIG. 4 shows the relationship between the interface circuit of FIG. 1 and other circuits of the slave station.

The part surrounded by dotted lines is the interface circuit.
A control circuit 1 in the interface circuit is connected to the decoder and the encoder. The ringer generation circuit includes the ringer signal generation circuit 2, LPF 3, and transformer 4, and the off-hook detection/delay circuit includes the delay circuit 6, switch 5, and photocoupler 14, respectively.

When the control circuit 1 receives a call at its own terminal, it sends the signal shown in FIG. The signal shown in b is sent out to the 2-Wire.

At this time, since current also flows through the photocoupler 14 in the negative portion (hatched area) in FIG. 2b, 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 in 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, since such a measure is taken, there is a certain time delay in off-hook detection, and a problem arises in that the ringer continues to ring during that time. 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 drawback was that the signal power was reduced.

It is an object of the present invention to prevent malfunctions of the off-hook detection circuit and eliminate delay time in off-hook detection by controlling the off-hook detection circuit using a ringer signal, and furthermore, to control the off-hook detection circuit using a ringer signal. An object of the present invention is to provide an interface circuit in a slave station of a wireless telephone device, in which a ringer signal is supplied to a telephone set.

In order to achieve the above object, an interface circuit in a slave station of a wireless telephone device according to the present invention comprises:
The telephone is verified by the ringer control signal issued by the control circuit when a call arrives at the own terminal station2.
an interface circuit in a slave station of a wireless telephone device that 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 a gate circuit that outputs the ringer signal; a low-pass filter for removing waves; a transformer connected to the two wires to which the ringer signal from the low-pass filter is input; a photocoupler connected to the two wires for detecting an off-hook state of the telephone; and the photocoupler. When a switch inserted between a power supply and the telephone device detects the ringer signal in an on-hook state, the switch is turned on only when the ringer signal is positive, and when the telephone device is in an off-hook state, the switch is turned on. It consists of a switch control circuit that is always on.

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 an embodiment of an 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 has 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 outputs the signals shown in FIG. Outputs a ringer signal when off-hook is not detected.

The ringer signal is sent to the 2-Wire via the LPF 3 and the transformer 4, and a part of it is guided to the switch control circuit 11.

When the switch control circuit 11 is in the on-hook state (the off-hook information transmission line is at a high level), the light emitting diode side of the photocoupler 14 and the power supply +5V are connected only during the positive part of the ringer signal (the dotted line part in FIG. 2a).
Turn on the switch 13 inserted between the two. 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 set, and the ringer signal generating circuit 2 of power is delivered to the phone.

Also, on the off-hook detection circuit side, the photocoupler 14 does not operate depending on the negative portion of the ringer signal.
When the 2-Wire goes off-hook in response to this call, the positive part of the ringer signal is detected by the photocoupler 14, and the detection signal is sent directly to the control circuit 1 through the transmission line 8, so that it is immediately detected. An off-hook condition is detected and the ringer will not sound after going off-hook.

Once off-hook is detected, the switch control circuit 11 continuously switches off the photocoupler 1 as described above.
4 becomes operational.

As described in detail above, the present invention makes it possible to immediately transmit off-hook information without causing malfunction by preventing the off-hook detection circuit from operating for only a part of one cycle of the 16Hz ringer signal. It is possible to realize an interface circuit that can

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an example of a conventional interface circuit, Figure 2 is a signal time chart, and Figure 3 is a circuit diagram showing an example of a conventional interface circuit.
The figure is a circuit diagram showing an embodiment of an interface circuit according to the present invention. FIG. 4 is a circuit diagram showing the relationship between the interface circuit and other circuits of the slave station according to the present application. 1... Control 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.

Claims (1)

[Claims] 1 When an incoming call is received at the own terminal station, a ringer control signal issued by the 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 In an interface circuit in a slave station of a wireless telephone device that prevents the off-hook detection signal from being transmitted and sends the off-hook detection signal to the control circuit, the ringer control signal from the ringer signal generation circuit and the control circuit is inputted, and the ringer control signal from the control circuit is inputted. a gate circuit that outputs the ringer signal when the off-hook detection signal is not output; a low-pass filter that removes unnecessary waves from the output ringer signal; and a gate circuit that receives the ringer signal from the low-pass filter as input. a transformer connected thereto, a photocoupler connected to the two wires and detecting an off-hook state of the telephone, a switch inserted between the photocoupler and a power supply, and when the telephone detects the ringer signal while the telephone is on-hook. An interface circuit in a slave station of a radio telephone device, comprising a switch control circuit that turns on the switch only when the ringer signal is positive and always turns on the switch when the telephone is in an off-hook state.