JPH0430851Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a telephone set that is used by connecting a plurality of telephones in parallel to the same line.

(b) Conventional technology Conventionally, a system in which two or more telephones are connected in parallel through a single telephone line is generally referred to as a communal telephone system. Broadly speaking, there are two types of community telephone systems. One is that the handsets are connected in parallel through a control device called the base unit, and in addition to the general line for calls, there is a system for controlling the handsets from the base unit. One type has a control line and has functions for inter-extension communication such as secret call, hold, and transfer as disclosed in Japanese Patent Publication No. 59-7254. The telephones were simply connected, but each telephone was installed at its own location without a control line or base unit, and it did not have the function of inter-extension communication.

(c) Problems to be solved by the invention In the case of a communal telephone system that has the function of inter-extension calls as described above, when a telephone is talking on one telephone, another telephone connected to the telephone is placed in an off-hook state. A confidential function is provided to prevent interruptions by preventing the audio of a call from being heard by another phone. Therefore, the control line other than the telephone line should be connected to 2
Because the line installation, the circuit of each telephone, and the entire communal telephone system have become complicated circuit configurations, it is expensive to install the communal telephone system, and it takes time and effort to connect. It's not a thing. Therefore, as a communal telephone system that is inexpensive and easy to install, there is one that does not have the function of inter-extension communication, but simply has a plurality of ordinary telephones connected in parallel to one telephone line. However, in this case, since a regular telephone is simply connected, if one telephone is in the middle of a call and another telephone is placed off-hook, the voice of the call will be added to the other telephone and interrupted. In addition, if dialing is performed by mistake on a different telephone, the signal from the dialing is added to the telephone during the call as noise and interferes with the telephone call operation. The present invention aims to provide a telephone that solves this problem.

(d) Means for Solving the Problems The telephone of the present invention includes a diode bridge circuit connected to a telephone line, a voltage detection circuit connected to the diode bridge circuit for detecting the off-hook voltage of the telephone line, and the above-mentioned a dial pulse generation circuit connected to the diode bridge circuit and generating a dial signal; a hook control circuit connecting the diode bridge circuit and a telephone call circuit;
An alarm sound generation circuit connected to the telephone call circuit and configured to generate an alarm sound, and outputs an inoperation signal for a certain period of time to the telephone call circuit and dial pulse generation circuit, and at the same time outputs an operating signal to the warning sound generation circuit. It consists of a control circuit.

(e) Effect The telephone set of the present invention is connected in parallel to one telephone line, and when the telephone line is off-hook and the handset is picked up, a warning tone is emitted through the handset and the telephone line is connected in parallel. This is designed to stop the telephone from talking for a certain period of time.

(F) Embodiment An embodiment of the telephone according to the present invention will be described with reference to the drawings. 1 is a first telephone, and 2 is a second telephone having the same configuration as the first telephone 1 , and is connected in parallel with the first telephone 1 to one telephone line L, L'. 3 is a diode bridge circuit that is directly connected to the telephone lines L and L' and determines the polarity of the input signal;
4 is a ringing tone circuit that detects a ringing signal and generates a ringing tone; 5 is the ringing tone circuit 4;
A voltage detection circuit 6 is connected to the diode bridge circuit 3 and detects a change in the voltage of the telephone lines L and L'. When it detects that the voltage has reached the off-hook voltage, it outputs an output signal. Reference numeral 7 denotes a telephone circuit for carrying out a telephone call operation via the telephone lines L and L', and a telephone receiver 8 is used to make a telephone call, and is equipped with a mouthpiece 8a for transmitting calls and an earpiece 8b for receiving calls. There is. 9 is a hook control circuit that controls the connection between the diode bridge circuit 3 connected to the telephone lines L and L' and the communication circuit 7 in response to the raising and lowering operations of the handset 8, and raises the handset 8. In response to this, the connection relationship is brought into a closed state. Reference numeral 10 denotes a dial pulse generation circuit which generates dial pulses and sends out dial pulses corresponding to operations on the keyboard 11. 12, when the telephone lines L and L' are in an off-hook state due to the use of the other telephone, when the handset 8 is lifted, the handset 8 becomes operational, and a sound is generated to warn that the other telephone is in use. 13 is the voltage detection circuit 6;
After receiving the output from the hook control circuit 9, a signal is received from the hook control circuit 9 indicating that the telephone lines L, L' and the telephone call circuit 7 are in a closed state. and a warning sound generating circuit 12. The above circuit constitutes the first telephone 1 . Note that the second telephone 2 also has the same configuration.

Next, the operation of an embodiment of the telephone according to the present invention will be described. First, assuming that both the first telephone 1 and the second telephone 2 are in standby mode, the voltage between the telephone lines L and L' is the on-hook voltage.
Approximately 48V appears. In such a state, since the voltage of the telephone line is an on-hook voltage and is higher than a predetermined voltage, the voltage detection circuit 6 does not output a detection signal to the control circuit 13. Furthermore, the hook control circuit 9
The connection between the communication circuit 7 and the diode bridge circuit 3 is kept open. In such a state, when a ringing signal is applied to the telephone lines L and L', the ringing signal is detected by the ringing circuit 4 provided in both the first telephone 1 and the second telephone 2 , and is output through the speaker 5. It is emitted as a ring tone. In such an operating state, for example, when the first owner puts the second telephone 2 into an off-hook state and attempts to make a call using the second telephone 2 , the voltage between the telephone lines L and L' will be the off-hook voltage number V~ More than a dozen Vs appear. Thereby, the voltage detection circuit 6 of the first telephone 1 and the second telephone 2 detects the off-hook voltage and outputs an output signal to the control circuit 13 of the first telephone 1 and the second telephone 2 . , the control circuit 13 detects that the telephone lines L and L' have gone off-hook, but no change occurs, and the first owner uses the second telephone 2 to make a call with the caller. is being carried out. When the second owner picks up the handset 8 of the first telephone 1 in such a state, the hook control circuit 9 in the first telephone 1 closes the communication circuit 7 and the diode bridge circuit 3, and A signal indicating that the closed state has been reached is applied to the control circuit 13. As a result, the control circuit 13 outputs a signal for activating the warning sound generating circuit 12, and at the same time outputs a signal to the telephone call circuit 7 to disable the transmitting circuit section in the telephone call circuit 7 and a dial pulse generating circuit. 10 is output for a certain period of time (approximately 20 seconds), and a warning sound is generated to the second owner who picks up the handset 8 of the first telephone 1 to indicate that the first telephone 1 is in an inoperable state. The circuit 12 outputs a warning sound from the earpiece 8b via the receiver circuit section in the communication circuit 7. Further, in order to prevent dial pulses from being generated even if the second owner operates the keyboard 11, the dial pulse generation circuit 10 is made inactive for a certain period of time (approximately 20 seconds), and the communication circuit 7 is The transmitting circuit section is also rendered inactive for a certain period of time (approximately 20 seconds) so that the second owner's voice is not added to the telephone lines L, L' via the circuit section. By performing the above operations, the second telephone line, which is connected in parallel to one telephone line L, L' and is in a talking state,
This prevents interference from the first telephone 1 from being applied to the telephone 2 , and notifies the owner of the first telephone 1 that the telephone lines L and L' are in an off-hook state. Furthermore, the first
If a hold function is added to telephone 1 and second telephone 2 , if one is placed on hold, telephone line L,
Since L' is in an off-hook state, when the other telephone is off-hook, the other telephone emits a warning tone and becomes disconnected. Therefore, a problem arises in that it is not possible to put one party on hold and make a call with the other party. In such a case, each telephone is provided with a release button in order to add a signal to the control circuit 13 to stop the signal output from the control circuit 13, and by operating the release button, the warning sound can be stopped. Even if the telephone is placed in a state in which calls can be made, no problem will arise in the present invention.

(g) Effects of the invention This invention detects a drop in the voltage of the telephone line due to the use of one telephone, in telephones connected in parallel to one telephone line. Therefore, when one's own telephone is taken off-hook, a warning is generated from the handset of one's own telephone to notify that one of the telephones is in use, so the user can easily know that one of the telephones is in use. And it can be recognized immediately. In addition, since the warning sound is generated from the handset of the telephone, there is no need to provide a special speaker to emit the warning sound, and the present invention
This has the advantage that the configuration is simple. In addition, the present invention not only generates a warning sound, but also disables the call circuit and dial pulse generation circuit for a predetermined period of time, so that no noise is transmitted to the telephone in use. This has the effect of not bothering people who are talking.

[Brief explanation of drawings]

The figure is a circuit configuration diagram illustrating an embodiment of the present invention. Explanation of main drawing numbers, 6... Voltage detection circuit, 7...
Call circuit, 8... Handset, 9... Hook control circuit, 12... Warning sound generation circuit, 13...
control circuit.

Claims (1)

[Scope of utility model registration request] In a telephone set that is connected in parallel to one telephone line, there is a diode bridge circuit connected to the telephone line, and a voltage drop that is connected to the diode bridge circuit and occurs when the telephone line is off-hook. a dial pulse generation circuit connected to the diode bridge circuit and generating a dial signal when a dial operation is performed; A hook control circuit that connects a telephone circuit provided for making a telephone call, an alarm sound generation circuit that is connected to the telephone circuit and generates a warning sound through a handset, and detects the voltage detection circuit. a control circuit that controls the operations of the telephone call circuit, dial pulse generating circuit, and warning sound generating circuit based on the signal; 1. A telephone set, characterized in that a warning sound generation circuit generates a warning sound, and the telephone call circuit and dial pulse generation circuit are kept in an inoperable state for a predetermined period of time.