JPH04102349U - terminal device - Google Patents

Abstract

(57) [Summary] [Structure] By the loop of L1 of connection terminal 12 - relay contact 14a - relay contact 16 - phototransistor 18 - Zener diode 17 - relay contact 19 - relay contact 14b - L2 of connection terminal 12, phototransistor 1
8 detects whether the line voltage of the subscriber telephone line is lower than a predetermined voltage value, and based on the detection result, the control circuit 11 determines whether or not the subscriber telephone line is used by another terminal device 2. [Effect] A plurality of terminal devices can be connected to one subscriber telephone line without exchanging special control signals between the terminal devices.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a terminal device, and more particularly to a terminal device connected to a subscriber telephone line.

0002

[Conventional technology]

Conventionally, when multiple terminal devices are installed at the same location, this type of terminal device Connect a dedicated subscriber telephone line to each terminal device, or connect a single subscriber telephone line to each terminal device. Even when using a shared telephone line, line control signals must be exchanged between each terminal device. It had a configuration that took

0003

[Problem that the idea aims to solve]

The conventional terminal devices described above have various functions (for example, alarm notification, voice call, This is a dedicated device for realizing data loggers, etc.), so other terminal devices can be connected. If the circuit for connecting is not prepared, or even if it is prepared, It is necessary to connect the control signal line between terminal devices separately from the subscriber telephone line, and Depending on the device, it is not possible to share the subscriber telephone line with other terminal devices, and each The disadvantage is that a dedicated subscriber telephone line must be connected.

0004

[Means to solve the problem]

The terminal device of the present invention is a terminal device connected to a subscriber telephone line. Whether other terminal devices connected to the telephone line are using the subscriber telephone line. further comprising a line state detecting means for detecting whether the subscriber It is installed in the network control circuit that controls incoming and outgoing calls on telephone lines.

[0005]

【Example】

Next, the present invention will be explained with reference to the drawings.

[0006] FIG. 1 is a block diagram showing an example of a network control circuit of a terminal device according to an embodiment of the present invention. Ru.

[0007] In FIG. 1, the network control circuit of the terminal device 1 of this embodiment connects the connection terminal 12 to the subscriber telephone. Connect the line and connect the terminal device 2 to the connection terminal 13 which is connected to the connection terminal 12. Ru.

[0008] In addition, the network control circuit of the terminal device 1 sends data to L1 and L2 of the subscriber telephone line, respectively. Connect relay contacts 14a and 14b for communication or voice communication switching, and connect directly between lines. The current circuit closing coil 15 is connected, and the relay contacts 14a, 14b, and A call signal detection circuit 21 that detects a call signal via a relay contact 19 and a selection signal The selection sending circuit 20 that sends out the signal is connected to the relay contact 14a-relay contact 16. - Photocoupler 18 - Zener diode 17 - Relay contact 19 - Relay contact 1 4a loop is connected to the subscriber telephone line status detection means, and this entire network control circuit is connected. The control circuit 11 is configured to include a control circuit 11 for controlling the .

[0009] The network control circuit of the terminal device 2 also has almost the same configuration as the network control circuit of the terminal device 1 described above. However, illustration is omitted.

0010 Next, the operation of this embodiment will be explained.

[0011] In FIG. 1, a subscriber telephone line is connected to the connection terminal 12 of the terminal device 1, and the connection terminal 13 to the connection terminal 12 of the terminal device 2, one subscriber telephone line can be connected. The line is shared by two terminal devices 1 and 2.

0012 Detecting whether a subscriber telephone line is in use or not This is done by monitoring line voltage.

[0013] If the terminal device 2 is currently using the subscriber telephone line, the selection signal is being sent. If so, the relay contact 19 of the terminal device 2 has been switched to the selection signal sending circuit 20. , the line voltage of the subscriber telephone line will be approximately 7V or less. In addition, the terminal device 2 performs data communication. or during a call, the relay contacts 14a and 14b of the terminal device 2 are connected to the DC circuit. Since it is switched to the closing coil 15, the voltage is also about 7V or less.

[0014] When the subscriber telephone line is not in use, the line voltage is L1 is positive and L2 is negative potential, which is about 42 to 53V. Therefore, Zener die The photocoupler 18 operates when the zener voltage of the ode 7 is between 7 and 42V. If selected, when the terminal device 1 makes a call operation, the relay is activated under the control of the control circuit 11. When the contact 16 is closed and the photocoupler 18 is activated, the control circuit 11 connects to the subscriber telephone line. It is determined that the call is not in use and the call operation continues. Relay contact 16 closed If the photocoupler 18 does not operate, the control circuit 11 detects that the subscriber telephone line is terminal equipped. It is determined that the device is in use by device 2, and the call operation is delayed.

[0015] In addition, in response to incoming calls from subscriber telephone lines, each terminal device 1 and 2 is called. It is detected by the signal detection circuit 21 and the relay contact 14 is turned off under the control of the control circuit 11. Reply instead.

[0016] The control circuit 11 can determine that the signal from the subscriber telephone line is a call to its own terminal device. If the response is different, the operation will continue as is, and if it is different, it will be fixed as an invalid response. After a period of time, the relay contact 14 is restored.

[0017]

[Effect of the idea]

As explained above, the present invention can monitor the usage status of the same subscriber telephone line of other terminal devices. By providing line status detection means to detect multiple It is possible to connect terminal devices without exchanging special control signals between the terminal devices. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

[Explanation of symbols]

1, 2 Terminal device 11 Control circuit 12 Connection terminal 13 Connection terminal 14 for supplying subscriber telephone line to other terminal devices Relay contact (for data communication or voice call switching) 15 DC circuit closing coil 16 Relay contact ( 17 Zener diode 18 Photocoupler 19 Relay contact (for switching selection signal transmission circuit) 20 Selection signal transmission circuit 21 Calling signal detection circuit

Claims (2)

[Scope of utility model registration request] 1. A terminal device connected to a subscriber telephone line, comprising line status detection means for detecting whether another terminal device connected to the subscriber telephone line is using the subscriber telephone line. A terminal device characterized by: 2. The terminal device according to claim 1, wherein the line state detection means is provided in a network control circuit that controls incoming and outgoing calls on the subscriber telephone line.