JPH0350936A - Response circuit for telephone set - Google Patents

Abstract

PURPOSE:To apply the title reply circuit for a reply circuit of all telephone sets independently of the presence of a handset by forming a DC loop with a tact switch turned on so as to make a telephone set a busy state and so as to made the telephone set into a standby state with the 2nd ON of the tact switch. CONSTITUTION:When an incoming call reaches a telephone set 10, the user turns on a tact switch SW 14. Thus, a current from a telephone line L is charged in a capacitor 15 and the voltage is applied to a power terminal VCC of a FF 17. As a result, a transistor(TR) 1 of a DC circuit 16 is turned on, the circuit 16 is closed and a DC loop is formed to the line L and the telephone set 10 is made busy with an opposite side. when the user closes a SW 14 at the end of a call, a photocoupler PC 2B detects it, a photodetector B is turned on and the FF 17 stops its operation. As a result, the TR 1 of the circuit 16 is turned off, the circuit is opened, the DC loop is opened, resulting that the telephone set 10 is in the standby state.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to answering circuits for telephones.

[Prior Art] In a telephone, when a call is received from a telephone office line, a DC loop is formed on the telephone office line, and the DC loop in parentheses is maintained to connect the telephone to the other party's telephone. A response circuit is used.

Conventionally, the above response circuit includes (a hook switch that turns on and off in conjunction with raising and lowering the aJ handset, and (b) a lock that turns on and off by manual operation and fixes this on/off state until it is operated again. or (e) a tact switch configured with a battery or a supercapacitor as a power source.

[Problem to be solved by the invention] However, the above prior art includes the following (A), CB)
, ((:) has a problem.

(A) Those using a hook switch cannot be applied to telephones without a handset.

(B) A lock switch that uses a lock switch has a long operating stroke, making it difficult to adopt a waterproof structure in which the switch body is covered with a waterproof sheet.

(C) Those using a tact switch consume communication current as a power source for a battery or a supercapacitor, so the quality of communication deteriorates.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone response circuit that can be applied to all telephones regardless of whether they are equipped with a handset, has a small operation stroke, and has good call quality.

[Means for Solving the Problems] The present invention forms a DC loop on the telephone office line when a call is received from the telephone office line, and maintains the DC loop in parentheses, thereby directing the telephone to the other party. In the response circuit of the telephone set, which is connected to the telephone set, there is a manually operated tact switch, and first and second switch-on detection devices connected to the telephone office line in series with the tact switch, and which detect when the tact switch is turned on. a capacitor that is connected to the telephone office line and starts charging on condition that the first switch-on detector detects that the tact switch is turned on; and a capacitor that is connected to the telephone office line and starts charging together with the telephone office line. A DC circuit forming the DC circuit and a charging voltage of the capacitor are applied to start operation, and the DC circuit is closed to form the DC loop, and the DC loop is connected to the power supply voltage from the telephone office line. and a control circuit that continues to operate when the DC voltage is applied, and stops operating on the condition that a second switch-on detector detects that the tact switch is turned on, and opens the DC loop by opening the DC circuit. This is how it was done.

Note that the term "tact switch" in the present invention refers to a non-locking switch that is turned on when an operating force is applied and immediately turned off when the operating force is released.

[Operation] The response operation of the telephone according to the present invention is performed as shown in (1) to (6) below.

(1) In response to the arrival of an incoming signal, the user turns on the tact switch.

(2) When the first switch-on detector detects that the tact switch is turned on, the electrolytic capacitor starts charging.

(3) The charging voltage of the capacitor is applied to the control circuit.

(4) The control circuit starts operating according to (3) above and closes the DC circuit. As a result, a DC loop is formed in the telephone office line, and the telephone is connected to the other party's telephone and a call is in progress.

At this time, the control circuit continues to operate by being supplied with the power supply voltage from the telephone office line forming the DC loop.

(5) At the end of the call, the user turns on the tact switch.

(6) When the second switch-on detector detects that the tact switch is turned on, the control circuit stops operating and opens the DC circuit. This opens the DC loop and puts the telephone into a standby state.

However, according to the present invention, the following (A) (B) (C)
It has the function and effect of

(A) Answer circuits can be configured for all telephones, whether or not they are equipped with a handset.

(B) Since the tact switch has a small operation stroke,
A waterproof structure in which the switch body is covered with a waterproof sheet can be easily adopted.

(C) Since a capacitor is used as a charging element for using a tact switch, the quality of communication can be improved.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a timing diagram.

Telephone I! 10 is a ringer circuit 11 as shown in FIG.
, a response circuit 12, and a telephone communication circuit 13.

The response circuit 12 forms a DC loop on the telephone office line when a call is received from the telephone office line to the telephone 10, and maintains this DC loop to connect the telephone 6!10 to the other party's telephone. They are connected to each other to enable communication using the communication circuit 13.

The response circuit 12 includes a tact switch 14 that is manually operated.

The response circuit 12 also connects a tact switch 14 to the telephone office line.
The first and second photocouplers Pct PC2 are connected in series with each other and detect whether the tact switch 14 is turned on.
Each light emitting element A is provided.

Further, the response circuit 12 is connected in series with the light receiving element B of the first photocoupler Pct to the telephone office line, and the first photocoupler PCI detects that the tact switch 14 is turned on, and the photocoupler PCI An electrolytic capacitor 15 is provided that starts charging on the condition that the light receiving element B of is turned on.

The response circuit 12 also includes a DC circuit 16 that is connected to the telephone office line and forms a DC loop with the telephone office line. The DC circuit 16 includes resistors R6, R7, and a transistor T.
Constructed by RI.

Furthermore, the response circuit 12 includes a general-purpose flip-flop (7411G73) 17 that constitutes a control circuit.

The flip-flop 17 starts operating when the charging voltage of the electrolytic capacitor 15 is applied to the power supply terminal Vcc, and the output terminal Q rises to a high level due to the time constant (R3, C2) of the clock terminal CL, and as a result, the DC circuit 16 TRs
By turning on I and closing the DC circuit 16, a DC loop is formed in the telephone office line.

The power supply terminal Vcc of the solid flop 17 is connected to the DC circuit 16 which is interposed between the telephone office line and the communication circuit 13.
The collector terminal of the transistor TR2 driven by the transistor TR2 is connected to the collector terminal of the transistor TR2. As a result, after the DC loop is formed, the flip-flop 17 is applied with the power supply voltage of the telephone office line through the collector terminal of the transistor TR2, continues to operate, and as a result maintains the DC loop.

Moreover, the flip-flop 17 is a second photocoupler PC.
2 is connected to the reset terminal CLR, and the second photocoupler PC2 detects that the tact switch 14 is turned on at the end of the call, and the condition is that the photocoupler PC2 turns on. The operation stops, and as the reset terminal CLH goes low, the output terminal Q falls to a low level, and as a result, the transistor TRI of the DC circuit 16
is turned off and the DC circuit 16 is opened to open the DC loop.

Next, the response operation of the telephone 10 will be explained (see FIG. 2).

(1) When receiving a call, an incoming call signal (16Hz 75V) arrives from the telephone exchange equipment. The incoming signal is rectified by the rectifier circuit and drives the ringer circuit 11. This results in
The ringtone sounds.

The user hears this ringtone and presses the tact switch 14 (
Turn on SW).

(2) A current from the telephone office line flows through the light emitting element A of the first photocoupler PCI, and it becomes possible to detect whether the Takto Switch 14 is turned on. Along with this, the light receiving element B of the first photocoupler PCI is turned on, and the electrolytic capacitor 1
Current from the telephone office line flows into 5, and charging begins.

(3) The charging voltage of the electrolytic capacitor 15 is applied to the power supply terminal Vcc of the flip-flop 17.

(4) The flip-flop 17 starts operating according to (3) above, and the output terminal Q rises to a high level due to the time constant (R3, C2) of the clock terminal CL, and as a result, turns on the transistor TRI of the DC circuit 16. , the DC circuit 1
By closing 6, a DC loop is formed in the telephone office line. As a result, the telephone 10 is connected to the other party's telephone, and a call is in progress.

At this time, the flip-flop 17 continues to operate by being supplied with the power supply voltage from the telephone office line forming the above-mentioned DC loop.

(5) At the end of the call, the user turns on the tact switch 14.

(6) The flip-flop 17 is a second photocoupler P
C2 detects that the tact switch 14 is turned on, and the photocoupler PC2 stops operating on the condition that the light receiving element B turns on. That is, the flip-flop 17
When the light receiving element B of the photocoupler PC2 is turned on, the reset terminal CLR goes to a low level, and the output terminal Q falls to a low level.As a result, the transistor TRI of the DC circuit 16 is turned off, and the DC circuit 16 is turned off. By opening, the DC loop is released. As a result, the telephone 10 enters a standby state.

Next, the operation of the above embodiment will be explained.

(A) A response circuit can be configured for all telephones 10, regardless of whether or not they are equipped with a handset.

(B) Since the tact switch 14 has a small operation stroke, it has good operability.

Furthermore, since the operating stroke is small, a membrane switch in which the switch body is covered with a waterproof sheet can also be used.

(C) Since the electrolytic capacitor 15 is used as a charging element for using the tact switch 14, the call quality can be improved, and a response circuit equipped with a tact switch can be used in a telephone that does not have a local power source (AC power source, battery, supercapacitor). can be realized with a simple configuration.

(D) By employing two photocoupler PC1 and PC2, the start and end of a call can be operated with a single tact switch 14, resulting in good operability.

[Effects of the Invention] As described above, according to the present invention, it is possible to configure a telephone response circuit that can be applied to all telephones regardless of whether or not they are equipped with a handset, has a small operation stroke, and has good call quality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a timing diagram. 1o...Telephone, 12...Response circuit, 14...Tact switch, 15...Electrolytic capacitor, 16...DC circuit, 17...Flip-flop (control circuit), L...Telephone Local line, PCT...first photocoupler (first switch-on detector) PC2...second photocoupler (second switch-on detector)

Claims (1)

[Claims] (1) In a response circuit of a telephone that connects the telephone to the other party's telephone by forming a DC loop on the telephone office line and maintaining this DC loop when a call is received from the telephone office line to the telephone. , a manually operated tact switch, first and second switch-on detectors each connected to the telephone office line in series with the tact switch and detecting the on state of the tact switch; and connected to the telephone office line; A capacitor that starts charging when a first switch-on detector detects that a tact switch is turned on; a DC circuit that is connected to a telephone office line and forms the DC loop with the telephone office line; and a capacitor charging It starts operating when voltage is applied,
The DC loop is formed by closing the DC circuit, and the power supply voltage from the telephone office line forming the DC loop is applied to continue operation, and the second switch-on detector is connected to the tact switch. 1. A response circuit for a telephone set, comprising: a control circuit that stops operating on the condition that ON is detected, and opens the DC loop by opening the DC circuit.