JPH03268648A - Network controller for multi-connection - Google Patents

Abstract

PURPOSE:To attain automatic dialing in the multi-connection state with one channel and to improve the line utility by providing a voltage detection circuit for monitoring the network state. CONSTITUTION:Diodes D1-D5 of a voltage detection circuit applies full wave rectification to a voltage of a line so that a voltage is applied to a zener diode D1 and a photocoupler T1 in a prescribed direction. The zener diode D1 is an element deciding a line voltage VT starting a current to the photocoupler T1 and the voltage VT is decided between voltages V2 and V3. A resistance of a resistor R1 is selected to limit the current for a forward current activating the photocoupler T1 at a voltage between the VT and the V3 and being a current value or below by which an exchange discriminates a loop.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a network control device having an automatic calling function for an analog telephone network, and particularly to a network control device suitable for a multi-connection state.

[Conventional technology 1] Conventionally, in order to connect multiple network control devices with an automatic dialing function to one line of an analog telephone network, another transmission path for transmitting a line-in-use indication is required in addition to the one line. Met.

[Problems to be Solved by the Invention] In the above-mentioned prior art, in addition to one line communication path, there is another communication path for transmitting a line-in-use indication for automatic dialing, and its transmitting circuit and receiving circuit are controlled by the respective networks. The drawback is that it cannot be performed unless it is installed in the device.

The purpose of the present invention is to eliminate such drawbacks, and to accomplish the following:
An object of the present invention is to provide a network control device that can automatically make calls in a multi-connection state on a line communication path.

[Means for Solving the Problems] The present invention is characterized in that a network control device comprising a dial sending circuit, a partner response detection circuit, and a call detection circuit is provided with a voltage detection circuit for monitoring the state of the network.

[Function] The relationship between the line status and voltage of the analog telephone network is shown in Figure 2 for outgoing calls and in Figure 3 for incoming calls.

During transmission operation, when the loop is closed to the line, the line voltage changes from Vl to V. When the selection signal is sent, in the case of the PB double signal, V from between V and Vj,
will change to When the other party is calling, the voltage is between vl and ■. The voltage whose polarity is reversed when the other party responds is the voltage between vl and 73.

When you end a call during a call, the number changes from ■1 to ■2 to V.

During incoming call operation, voltage between ■3 and V4 is applied while receiving a ringing signal. When you respond to an incoming call, the voltage changes from vl to 72. After the response, the voltage changes the same as the sending operation.

In the transmission operation, while the selection signal is being sent, it takes two values: the line state voltage and the line unused state. In order to avoid mistakenly determining that the line is not in use when the selection signal is being sent, the voltage V while the selection signal is being sent is short due to the DP double signal break time (70m5 or less in IOPPS), so the voltage is used to determine if the line is not in use. If V continues longer than the DP double signal break time, it can be determined that the line is in use while the selection signal is being sent.

In an incoming call operation, the ringing signal covers the entire voltage range from the line in use to the line not in use.

The calling signal is determined by a calling signal detection circuit that detects the voltage of V, and it can be determined that the line is in use.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The outgoing operation is performed from the communication terminal device through the automatic outgoing data line 5.
The control circuit 10 receives the outgoing request via the control circuit 10. The control circuit 10 uses the voltage detection circuit 9 to determine whether the line is in use or not, and then uses the ringing signal detection circuit 8 to determine whether there is an incoming call based on the presence or absence of a ringing signal. The line is in use,
If a call is received, a line busy indication is sent to the communication terminal device via the automatic call data line 5, and the call is terminated. When the line is not in use, the control circuit 10 operates the loop closing H relay and sends out a selection signal from the dial sending circuit 6. Detects the other party's response by the other party's response detection circuit 7 LC
Activate MLI, 2 relay, restore H relay, connect telephone lines 1 and 2 to cold flow line RET, capacitor C9 communication path 3
, 4, connects to the communication terminal device and enters the communication state. From a non-communicating device via the automatic transmission data line 5,
When the control circuit 10 receives the line restoration request, it restores the C and ML relays 1 and 2, opens the loop for the telephone lines 1 and 2, and makes the telephone lines unused.

Next, the voltage detection circuit will be explained. D2,3°4.5
rectifies the line voltage and uses Zener diode DI,
A voltage is applied to the photocoupler T1 in a certain direction. The Zener diode DI is an element that determines the line voltage vT at which current begins to flow to the photocoupler T1, and VA is determined between V and V. The resistor R1 is for current limiting, and is selected so that a forward current that allows the photocoupler T1 to operate can flow between the V and V1, and the current is below the current value at which the traffic checker determines a loop.

〔Effect of the invention〕

According to the present invention, it is possible to determine the usage status of a line. As a result, a plurality of automatic transmission network control devices can be connected to one line, and the utilization rate of the line can be dramatically increased.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the line status during outgoing calls on the analog telephone network, and FIG. 3 is a diagram showing the line status during incoming calls on the analog telephone network. be. 1.2...Telephone line 3.4...Communication path 5...Data line for automatic transmission 6...
・Dial sending circuit 7 ・・・・・・・・・ 8 ・・・・・・・・・ 9 ・・・・・・・・・ 10 ・・・・・・・・・ Dl ・・・・・・・D2~5 R1...T1...... Other party's response detection circuit Calling signal detection circuit Voltage detection circuit Control circuit Zener diode Rectifier diode F! Figure 3

Claims (1)

[Claims] 1. A network control device for multi-connection, characterized in that a network control device consisting of a dial sending circuit, a partner response detection circuit, and a call detection circuit is provided with a voltage detection circuit for monitoring the state of the network.