JPH0536956U - Branch interruption prevention telephone - Google Patents

Abstract

(57) [Abstract] [Purpose] An electronic analog telephone characterized by notifying that one of the branched analog telephones is busy and not giving any interference even if the telephone is off-hook accidentally. obtain. [Configuration] Telephone line voltage monitoring circuit 21 and current detection circuit 22
If the other branch terminal is in use, the LED lamp 25 of its own terminal that is not in use
Is turned on and the switcher contact 32 is switched to disconnect the terminal from the telephone line in use. [Effect] To obtain an electronic analog telephone that not only informs that another branching terminal is in use, but does not disturb the call even if the terminal itself is operated by mistake.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 This invention relates to an electronic analog telephone.

[0002]

[Prior Art]

 FIG. 4 is a block diagram of a recent electronic analog telephone. In the figure, 1 is a telephone line, 2 is a hook switch, 3 is a tone ringer circuit, 4 is a diode bridge, 5 is a speech network circuit, 6 is a dialer circuit, 7 is a numeric keypad, 8 is a handset, 9 is a speakerphone circuit, and 10 is a speakerphone circuit. Is a speaker and 11 is a microphone.

Next, the operation will be described. (1) At the time of incoming call Since the RG signal is sent from the telephone line 1, the tone ringer circuit 3 detects the RG signal and sends the tone ringer to the speaker 10 to notify the incoming call. When the receiving side picks up the handset 8, the hook switch 2 is closed, and a current flows through the diode bridge 4 to the speech network circuit 5 to notify the central office that it has responded. The speech network circuit 5 has a hybrid function of converting two lines on the telephone line side into four lines, a side tone suppressing function, and the like. In the case of a handset call, the call is made using the handset 8. However, in the case of a handsfree call, the speakerphone circuit 9 amplifies the audio signal and the speaker 10 hears the voice from the other party. Sent to the speech network circuit 5. (2) At the time of outgoing call First, by taking the handset 8, the hook switch 2 is closed, and the call current flows through the route of the telephone line 1, the hook switch 2, the diode bridge 4, and the speech network circuit 5. When a dial tone is transmitted from the telephone station and then dialed using the ten-key pad 7, the dialer circuit 6 transmits the corresponding dial pulse or PB signal to the telephone line 1. If the other party answers, the handset 8 makes a call.

[0004]

[Problems to be solved by the device]

 Since the conventional electronic analog telephone is configured as described above, when used in a branch, one terminal cannot use the other terminal while it is in use, and the other terminal goes off-hook. There was a problem that it interfered with a call in progress.

The present invention has been made to solve the above-mentioned problems, and when the branch is in use, the other terminal is in use by lighting the lamp of its own terminal. The purpose is to obtain an electronic analog telephone.

[0006]

[Means for Solving the Problems]

 The telephone according to the present invention determines the statuses of its own terminal and other terminals from the output signals of the voltage monitoring circuit that monitors the line voltage and the current monitoring circuit that detects the presence or absence of loop current, and the other branch is in use. If it is, the lamp of the own telephone is turned on.

Further, by providing the switcher contact, when another terminal is in use, the own terminal is disconnected from the telephone line.

Alternatively, the power supply to each circuit in the own terminal is stopped by the output of the state determination circuit.

[0009]

[Action]

 In the electronic analog telephone configured as described above, when the other telephone is busy, the line voltage greatly changes compared to when it is not used. Also, at this time, since the current does not flow to the own terminal, these conditions are detected, the lamp of the own terminal is turned on, and the other terminal is informed that it is in use.

Further, under the above conditions, the switcher contact is operated in response to the output of the state determination circuit, and the unused own terminal is disconnected from the telephone line in use, and the operation of the own terminal causes a busy call. Try not to disturb the call.

Similarly, under the above conditions, the output of the state determination circuit is received to stop the power supply to each circuit in the unused terminal so that the operation of the own terminal does not interfere with the call in progress. To

[0012]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 11 are exactly the same as the block diagram of the above conventional electronic analog telephone. 21 is a voltage monitoring circuit that monitors the voltage of the telephone line, 22 is a current detection circuit that detects the presence or absence of loop current, and 23 is a status determination that determines the status of the own terminal by the output of the voltage monitoring circuit 21 and current detection circuit 22. Reference numeral 24 is a lamp drive circuit, and 25 is an LED lamp.

In the electronic analog telephone configured as described above, the normal call originating / receiving operation is the same as before, but when the other branch terminal is in use, the line voltage of the telephone line is not used. It greatly changes from -48V at the time to -10V or more. This change is detected by the voltage monitoring circuit 21. Since the loop current does not flow because the own terminal is not in use, the current detection circuit detects no loop current. That is, when another branch terminal is in use and its own terminal is not in use, there is a voltage change and no loop current.Therefore, this condition is determined by the state determination circuit 23. At this time, the lamp drive circuit By controlling 24, the LED lamp 25 is turned on to notify that another branch terminal is in use.

Example 2. In the first embodiment, the LED lamp is turned on and only the lamp notifies that the other terminal of the branch is in use. However, in the present embodiment, a switcher contact is provided in addition to the indication of the lamp so that the unused terminal is not used. The above effect can be expected by adopting a method that does not interfere with a call in progress even if the user's own terminal is accidentally operated by disconnecting the current terminal from other terminals in use.

FIG. 2 is a block diagram of a branch interruption prevention telephone provided with a switcher contact. In the figure, 1 to 11 and 21 to 25 are exactly the same as the block diagrams shown in FIGS. Reference numeral 31 is a switcher drive circuit, and 32 is a switcher contact.

Next, the operation will be described. Although the voltage and current are monitored and the LED lamp is turned on when the other terminal of the branch is not in use and its own terminal is not in use, it is exactly the same as that shown in FIG. 1, but in FIG. The switcher drive circuit 31 is controlled by the output of the state determination circuit 23 and the switcher contact 32 is switched to disconnect the unused terminal from the telephone circuit 1 in use.

Example 3. FIG. 3 is a block diagram of a branch interruption preventing telephone set showing another implementation method in which a call in progress is not disturbed even if the own terminal which is not in use is operated by mistake. 1 to 11 and 21 to 25 are exactly the same as the block diagrams shown in FIG. 1 and FIG. Reference numeral 41 is a power supply control unit that controls power supply to each circuit in the own terminal, and 42 is a power supply control line to each circuit.

The embodiment shown in FIG. 3 will be described. In FIG. 2, the switcher contact is operated to disconnect the terminal from the telephone line in use, but in the present embodiment, the power supply control unit 41 is controlled by the output of the state determination circuit 23 to supply the power supply control line 42. Then, the power supply to each circuit is stopped and the function of the self terminal is killed, and the same effect as that of the second embodiment is obtained.

[0019]

[Effect of the device]

 As described above, according to the present invention, an electronic analog telephone is provided with a state determination device when a branch is used, and when another terminal is in use, an LED lamp notifies the switch and a switcher contact is made. However, there is a service merit that even if the terminal is accidentally off-hook by disconnecting the terminal from the telephone line, it does not interfere with other terminals in the call.

[Brief description of drawings]

FIG. 1 is a block diagram of an electronic analog telephone showing a first embodiment of the present invention.

FIG. 2 is a block diagram of an electronic analog telephone showing a second embodiment of the present invention.

FIG. 3 is a block diagram of an electronic analog telephone showing a third embodiment of the present invention.

FIG. 4 is a block diagram of a conventional electronic analog telephone.

[Explanation of symbols] 1 Telephone line 2 Hook switch 3 Tone ringer circuit 4 Diode bridge 5 Speech network circuit 6 Dialer circuit 7 Numeric keypad 8 Handset 9 Speakerphone circuit 10 Speaker 11 Microphone 21 Voltage monitoring circuit 22 Current detection circuit 23 State determination circuit 24 Lamp Drive circuit 25 LED lamp 31 Switcher drive circuit 32 Switcher contact 41 Power supply control unit 42 Power supply control line

Claims (1)

[Scope of utility model registration request] 1. A branch interruption preventing telephone having the following (a) to (d): (A) A voltage monitoring circuit for monitoring the voltage of the telephone line; (b) a current monitoring circuit for detecting the presence / absence of loop current; The state determination circuit that knows the state of (4) and (d) the state determination circuit of (3) above receives the signal output only when the other terminal is in use and the own terminal is not in use, and turns on the LED lamp. Lamp drive circuit to let.