JPS6331345A - Push-button telephone system - Google Patents

Abstract

PURPOSE:To eliminate a howling phenomenon, or the hit of a line, by constituting a system so that a hook switch which inputs the presence/absence of a handset call to a microprocessor, is actuated with a timing faster than that of the hook switch which connects between a line and the call circuit of a telephone set. CONSTITUTION:At the time of monitoring the on-hook of a central office line, a monitor relay 11 is turned on, and the call loop of the central office line is generated by a call circuit 6, thereby, the central office line is captured. Also, a link switch 13 is turned on by a control signal from the microprocessor 10, and a state to output the sound of the central office line from a speaker 15 is generated. When a mode is shifted from central office line on-hook monitoring to an off-hook handset call, the link switch 13 is turned off first by the control signal from the microprocessor 10 by turning on a hook switch 5, and the loudspeaking of the speaker is completed, and at the next, the mode is shifted to the handset call by turning on a hook switch 4, then a microphone 8 is turned on. The monitor relay 11 always remains in an ON state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a button telephone device having an on-hook monitoring function.

BACKGROUND OF THE INVENTION Conventionally, in a button telephone device having an on-hook monitoring function, in addition to a first hook switch that connects a telephone line to a telephone communication circuit, in conjunction with the first hook switch, the presence or absence of a handset call is inputted to a microprocessor. a second hook switch, and the microprocessor
Information from the hook switch is used to control on/off of the on-hook monitor amplifier and on/off control of the on-hook monitor relay.

The problem that the invention seeks to solve However, in the above-mentioned conventional button telephone device.

In the process of transitioning from line on-hook monitoring to off-hook handset communication, the following two problems occurred due to timing discrepancies between the first hook switch and the second hook switch.

1) If you turn on the first hook switch and then turn on the second hook switch, the first hook switch turns on, which turns on the handset microphone, but the speaker drive amplifier remains on. Therefore, a howling phenomenon occurs.

2) If you turn on the second hook switch and then turn on the first hook switch, when the second hook switch turns on, the monitoring relay turns off, and at that point, the first hook switch is still on. Since it remains off, the line will be momentarily disconnected and the call will be dropped.

The present invention is intended to solve such conventional problems, and is an excellent method that does not cause any howling phenomenon or instantaneous line interruption even if there is a difference in the timing of turning on the first and second hook switches. The object of the present invention is to provide a button telephone device.

Means for Solving the Problems In order to achieve the above object, the present invention changes the control timing of the monitor relay so that the second hook switch is turned on and then the first hook switch is turned on. The inside is configured so that a monitoring relay is always turned on regardless of whether it is on-hook or off-hook.

Therefore, according to the present invention, by turning on the second hook switch and then turning on the first hook switch, first the amplifier for driving the speaker is turned off, and then the microphone of the handset is turned on. This prevents howling.

During a line call, the relay for monitoring is always on and captures the line, so even when the handset is on (on-hook monitor) and goes off-hook, there is no momentary disconnection of the line.Q Example FIG. 1 shows the configuration of an embodiment of the present invention.

Reference numeral 1 denotes a central office line relay, which switches the telephone to either the central office line side or the extension line side. 2 is a central office line, 3 is an extension line, 4 is a first hook switch, and 6 is a second hook switch, and these hook switches 4.5 are configured to work in conjunction with each other. However, the configuration is such that the timing at which the second hook switch 5 is turned on is earlier than the timing at which the first hook switch is turned on. The state of the hook switch 4.5 in FIG. 1 indicates an on-hook idle state.

6 is the telephone call circuit, Ryo is the receiver of the handset,
8 is a microphone, and 9 is a big amplifier transformer for receiving audio from the central office line. A direct current loop during a telephone call on the central office line is created by the telephone call circuit 6. 1o is a microprocessor that controls the operation of the telephone, and 11 is a monitoring relay, which is controlled by the microprocessor 1o. Reference numeral 12 denotes a central office line key, which, when pressed, captures the central office line. When pressed in the on-hook state, the microprocessor 1
Controlled by o. Reference numeral 13 denotes a link switch for controlling on/off of the station line received voice from the pickup transformer 9, and is controlled by the microprocessor 10 to be turned on during on-hook monitoring. 14 is an amplifier during on-hook monitoring, and 15 is a speaker.

When monitoring the office line on-hook, the monitor relay 11 is turned on, and the communication circuit 6 creates a communication loop for the office line.
Capture the central office line. Further, the link switch 13 is turned on by a control signal from the microprocessor 1o, and the speaker 16 becomes in a state in which central line audio is output. When transitioning from a central office line on-hook monitor to an off-hook handset call, first the hook switch 6 is turned on, and a control signal from the microprocessor 10 is used to
The link switch 13 is turned off, the speaker amplification ends, and 1
Next, by turning on the hook switch 4, the handset conversation is transferred and the microphone 8 is turned on. Monitor relay 11 remains on at all times.

FIG. 2 shows a timing chart when transitioning from an on-hook monitoring state to an off-hook external line call.

a indicates the on/off state of the office line relay 1, 6 indicates the on/off state of the link switch 13, C indicates the on/off state of the handheld microphone 8, and d indicates the on/off state of the monitor relay 11, respectively. . A indicates the timing when the second hook switch 5 is turned on, and B indicates the timing when the first hook switch 4 is turned on. As is clear from this timing chart, link switch 1
After microphone 3 is turned off and speaker amplification ends, microphone 8 is turned off.
is turned on, so no howling phenomenon occurs. Also,
Since the monitor relay 11 is always on during acquisition of the central office line, even when changing from timing A to timing B, no instantaneous disconnection of the central office line occurs and the communication loop can be maintained.

Effects of the Invention As is clear from the above embodiments, the present invention provides a first hook switch that connects a line and a telephone call circuit to a second hook switch that inputs the presence or absence of a handset call to a microprocessor.
The hook switch is configured to turn on earlier in terms of timing, so the monitor speaker is always off when the hand-sent microphone is turned on, and there is no feedback phenomenon at all. has advantages. Furthermore, since the monitor relay is configured to keep the line on at all times during acquisition of the office line, it has the advantage that momentary interruptions of the office line do not occur at all.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the button telephone device of the present invention, and FIG. 2 is a timing chart of essential parts of the embodiment. DESCRIPTION OF SYMBOLS 1... Office line relay, 2... Office line, 3... Extension line, 4... First hook switch, 5...° second hook inch, 6... Call circuit, 7...Handset receiver, 8...Handsect microphone,
9...Transformer, 1o...Microprocessor, 1
1... Monitor relay, 12... Office line key, 13
- Link switch, 14...Monitor amplifier, 15
-=Monitor speaker.

Claims (1)

[Claims] A first hook switch that connects the line and the telephone circuit, a second hook switch that operates in conjunction with the first hook switch and inputs its status to the microprocessor, and another hook switch that connects the line and telephone when on-hook. It consists of a link, an amplifier that amplifies the sound etc. from the line when the link is on when on-hook, and a speaker driven by the output of the amplifier, and the timing at which the first hook switch is turned on is determined. A button telephone device characterized in that the timing is set later than the timing at which the second hook switch is turned on.