JPH02162947A - Telephone set - Google Patents

Abstract

PURPOSE:To minimize an incoming call disabled state due to a permanent call by providing a detection circuit for howler tone, a control section controlling hooking on a hook switch with the detection signal and a switch circuit. CONSTITUTION:When a howler tone is sent from an exchange, a howler tone detection circuit 4 detects the tone and outputs the detection output to a control circuit 5. The control circuit 5 receives the output to apply control output to turn off a transistor(TR) 1 and to turn on a TR 2. Moreover, the control output is kept till a release signal is inputted. A channel circuit 3 is opened from a line by the control and an incoming circuit side 6 is connected to the line. Since it is similar to a conventional hook-on state, the incoming call is available, as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a telephone set, and particularly relates to a technique for minimizing inability to receive calls due to disconnection of the handset.

[Conventional technology]

In conventional telephones, in order to recover from a disconnected state, the switchboard sends out a howl sound to urge people around the telephone to recover.

In addition, if recovery measures were not taken, the signal would gradually become louder to call for more attention.

[Problem to be solved by the invention]

With conventional telephones, people in the vicinity must confirm the howling sound and restore the handset to an on-hook state.

On the other hand, since a large amount of electric power is required to transmit the howler sound, a method is adopted in which the signal is transmitted for a certain period of time, and if the signal is not restored, the signal transmission is interrupted, and the signal is repeatedly transmitted after a certain period of time.

Therefore, if there is no one around the telephone when the first howler sound is sent out, there is a drawback that it takes time to restore the telephone and the call cannot be received for a long time.

[Means to solve the problem]

The telephone according to the present invention includes a howler sound detection section, a control section for controlling the hook switch to an on-hook state 8 based on the detection signal, and a switch circuit.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

The calling circuit side hook switch 1 and the receiving circuit side hook switch 2 are interlocked. Trl is hook switch 1
is connected in series to the communication circuit 3 and the howler sound detection circuit 4.

Tr2 is connected in parallel to the hook switch 2 and connected to the incoming call circuit 6. The control circuit 5 is a howler sound detection circuit 4
The on/off control of Trl and Tr2 is performed by the output from the Tr1 and Tr2.

Next, the operation of this embodiment will be explained.

In the off-footer state, hook switch 1 is conductive and hook switch 2 is open, and in normal operation, Tr
i is in the on state and Tr2 is in the off state. When a howler sound is transmitted from the exchange, a howler sound detection circuit 4 detects this and outputs its output to a control circuit 5.

The control circuit 5 receives this output and performs a control output to turn Trl off and turn Tr2 on. Further, this control output is held until a release signal is input.

By this control, the calling circuit 3 side is disconnected from the line, and the receiving circuit 6 side is connected to the line. This is similar to the normal on-hook state, so it is possible to receive calls.

If an incoming call is received in this state, by inputting a release signal to the control circuit, the normal off-footer state is established, and the call becomes possible.

FIG. 2 shows a second embodiment of the invention. Tr21 is a communication circuit 22. The transistor Tr22 is a switch transistor that connects and disconnects the howler sound detection circuit 23 and the line, and Tr22 is a switch transistor that connects and disconnects the incoming call circuit 25 and the line.

The control circuit Tr21. Performs on/off control of Tr22.

Next, the operation of this embodiment will be explained.

Normally, in the on-hook state, an on-hook state signal (low level in this example) is input from the hook switch 21 to the control circuit 24, and the Tr21 is controlled to be in the off state and the Tr22 is controlled to be in the on state. When the off-hook state signal (high level) is input from the hook switch 21, the control circuit 24
Tr21 is turned on, Tr22 is turned off, and controlled to be in a talking state.

In this state, when the howler sound detection signal from the howler sound detection circuit 23 is input, the control circuit 24 turns Tr21 off regardless of the state of the hook switch 21.
By controlling 2 to be on, the state seen from the line is the same as when on-hook, and a call can be received.

This state is maintained until the on-hook state signal (low level) is input from the hook switch 21 once and the off-footer state signal (high level) is input again.

Therefore, if an incoming call is received when the on-hook state is automatically established due to the detection of a howler sound, the hook switch 21
Once on-hook, you can go off-hook to return to a normal conversation state.

〔Effect of the invention〕

As explained above, the present invention has a function of returning the telephone to the on-hook state by detecting the howler sound, so that it is possible to eliminate the state in which it is impossible to receive a call due to the telephone being disconnected from the receiver.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention, and FIG. 2 shows a second embodiment. 1...Hook switch on the communication circuit side, 2...
...Incoming circuit side hook switch, 3 and 22...
・Telephone circuit, 4 and 23... Howler sound detection circuit, 5 and 24... Control circuit, 6 and 25...
... Incoming circuit, Trl ... Hook switch 1
A transistor switch connected in series with Tj2...
...Transistor switch connected in parallel to hook switch 2, 21...Hook switch, Tr
21...Transistor switch on the communication circuit side, T
r22...Transistor switch on the incoming circuit side. Agent: Patent Attorney Shindo Uchihara

Claims (1)

[Claims] This telephone is characterized by having a means for detecting a howler sound sent from an exchange, and a means for using the detection signal to make the state as seen from the line equivalent to on-hook, regardless of the state of a hook switch.