JPS63300662A - Called party reply and lockout detection system - Google Patents

Abstract

PURPOSE:To detect a called party reply due to the polarity inversion of a line in distinction from the lockout due to power interruption of the line by providing two detection elements operated in a different polarity to the line. CONSTITUTION:Denoting the polarity of lines L1, L2 by +, - respectively at the initial state, a detection signal P1 from a photocoupler 11 as a detection element goes to 1 and a detection signal P2 from a photocoupler 12 goes to 0. Inverting the polarity of the lines L1, L2 by the called party reply, the signal P1 from the coupler 11 goes to 0 and the signal P2 from the coupler 12 goes to 1. Then in the case of denoting the polarity of the lines L1, L2 by -, + respectively at the initial state, the similar polarity inversion is applied. In case of the power supply interruption of the lines L1, L2, the signals P1, P2 go to 1. Thus, when the one coupler is moved from the operating state into the unoperating state and the other coupler is moved from the unoperating state into the operating state, it is detected as the called party reply due to the polarity of line and when both the couplers are in nonoperating state, it is detected as lockout.

Description

[Detailed Description of the Invention] [Summary] Using detection elements such as two relays and photocouplers that operate by voltage or current, regardless of the initial line polarity,
It detects the response of the called party and also detects that the power supply has been cut off due to lockout.

[Industrial application field]

The present invention detects a called party response due to line polarity reversal,
The present invention also relates to a called party response and lockout detection method for detecting a lockout caused by cutting off line power supply.

The network control device connected to the terminal device detects the called party's response by reversing the polarity of the line and applies a communication enable signal to the terminal device.Also, when the power supply is cut off due to lockout, It is necessary to detect this so as not to misidentify it as a called party response.

[Conventional technology]

FIG. 3 is an explanatory diagram of a communication network, in which terminal devices 21 and 22 are connected to an exchange 25 via network control devices 23 and 24, respectively. The network control devices 23 and 24 have functions such as calling, sending a dial number, detecting a called party response, and restoring. For example, when communicating from the terminal device 21 to the terminal device 22, In response to the communication request, the network control device 23 makes a call and sends the dial number of the terminal device 22 by receiving a dialable signal from the exchange [25].

The exchange 25 connects the terminal device 22 corresponding to this dial number.
If the terminal device 22 is in a receivable state, the network control device 24 sends a response signal to the exchange 25 by forming a loop or the like in response to the call. Based on the response signal from the called party, the exchange 25 performs bus settings, inverts the polarity of the calling party's line, and notifies the called party of the response.

The network control device 23 on the calling side detects this reversal of the polarity of the line, determines that it is a response from the called party, and sends a communication enable signal to the terminal device 21. The terminal device 21 starts sending data in response to this communication enable signal.

A conventional called party response detection circuit in the network control devices 23 and 24 has the configuration shown in FIG. 4, for example.

In the figure, 31 is a photocoupler, 32 is a photodiode, 33 is a phototransistor, 34 is a diode, 35.36 is a resistor, Ll and L2 are lines, and C1 and C2 are capacitors.

Capacitors CI and C2 are for cutting off direct current from the modem side, and lines Ll and L2 are connected to the exchange side. In the initial state, when the line L1 is depolar and the line L2 is unipolar, a forward voltage is applied to the diode 34 via the resistor 35, and a loop can be formed on the exchange side. Further, since a voltage of opposite polarity is applied to the photodiode 32 of the photocoupler 31, the phototransistor 33 is turned off, and the detection signal becomes high level ("1").

The called party responds to vAL1. When the polarity of L2 is reversed, a forward voltage is applied to the photodiode 32. Therefore, the photodiode 32 emits light,
Since the phototransistor 33 to which the light is incident is turned on, the detection signal becomes a low level (“0”).

Therefore, the line L1 in the initial state. The polarity of L2 is +
, -, the polarities of the lines L1 and L2 are reversed and become -2+ due to the called party's response, so the detection signal changes from "1" to "0" and the called party's response can be detected.

[Problem 3 to be solved by the invention: Contrary to the above case, if the polarities of lines Ll and L2 are each set to 110 in the initial state, the detection signal in the initial state will be "0". . When the polarity is reversed by the called party's response, the detection signal becomes "1". Even in the case of such a polarity relationship, the detection signal changes from “0” to “1”.
The called party's response can be detected by the change in the number of calls.

However, in this case, if the line power supply is cut off due to lockout due to the called party talking, etc., the phototransistor 33 is turned off, so the detection signal becomes "1".

That is, since the detection signal in the initial state is "0" and becomes "1" due to lockout, the detection signal becomes the same as the response of the called party, resulting in malfunction.

It is an object of the present invention to detect a called party response, regardless of the initial polarity of the line, and to also be able to detect a lockout.

[Means for solving problems]

The called party response and lockout detection method of the present invention includes the first
To explain with reference to the figure, detection elements 1 such as photocouplers and relays that operate with different polarities for the line,
2 is provided, and when one detecting element 1 transitions from an active state to a non-active state, and conversely, the other detecting element 2 transitions from a non-active state to an active state, the called party responds according to the polarity of the line. A lockout is detected when both of the two detection elements 1.2 become inactive.

[Effect]

Corresponding to the initial polarity of the line, one of the detection elements 1 becomes active or inactive, and the other detection element 2 becomes inactive or active, so when the line polarity is reversed next, One of the sensing elements 1 is in an inactive state or in an active state, and the other sensing element 2 is in an active state or in a non-active state.

Therefore, if the state of each detection element 1.2 is reversed, a called party response can be detected due to polarity reversal.

In addition, in the case of power supply interruption due to lockout, each detection element 1.
2 is in the inactive state, so it can be detected separately from the called party's response.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a main circuit diagram of an embodiment of the present invention, and 11.1
2 is a photocoupler as a detection element 1.2 (see Figure 1), 13.14 is a photodiode as a light emitting element of the photocoupler, 15.16 is a phototransistor as a light receiving element of the photocoupler, and 17 to 19 are phototransistors. Resistance, Ll,
L2 is a line.

CI and C2 are capacitors, and PI and P2 are detection signals.

Line L1 in the initial state. Set the polarity of L2 to +
, -, the detection signal P1 from the photocoupler 11 is "1" and the detection signal P2 from the photocoupler 12 is "0".
becomes. The called party responds to vAL1. When the polarity of L2 is reversed, the detection signal P1 from the photocube 11 becomes "0".
”, the detection signal P2 from the photocoupler 12 becomes “1”.

On the contrary, line L1 in the initial state. When the polarities of L2 are - and 10, respectively, the detection signal P1 from the photocoupler 11 is "0", and the detection signal P from the photocoupler 12 is "0".
2 becomes "1", and when the polarity of lines Ll and L2 is reversed by the called party's response, the detection signal P from the photocoupler 11
1 is “1”, and the detection signal R2 from the photocoupler 12 is “
0''.In other words, regardless of the polarity of the lines Ll and L2 in the initial state, when the polarity of the lines vAL1.L2 is reversed, the detection signals PL and P from the photocouplers 11.12
2 will be inverted.

In addition, in the case of power failure of lines Ll and L2, photocoupler lL
Detection signals PI and P2 from 12 are both "1".

Therefore, it can be detected separately from the called party's response.

The above operations are shown in the table below.

Note that the initial state is the initial state, the response is the called party response, L is lockout, × is power cutoff, and + and - are line Ll.

The polarity of L2, 1, 0, indicates the logic level of the detection signals PI, P2, "1", "0".

As mentioned above, without memorizing the initial polarity of the line, when there is a change in the logic level of the detection signals PI and P2, it is possible to detect that the called party has responded by reversing the polarity of the line. Detection signal P1. When both P2 become "0", it is possible to detect a lockout.

In the above embodiment, the photocoupler 1 is used as the detection elements 1 and 2.
1.12 is used, but it is also possible to use a relay that operates or does not operate depending on the polarity. It is also possible to use semiconductor elements such as transistors.

〔Effect of the invention〕

As explained above, the present invention uses two detection elements 1.2 that operate with different polarities with respect to the line,
It is able to distinguish and detect a called party's response due to reversal of line polarity and a lockout due to line power cut-off, and can reliably detect a called party's response and lockout for various initial line polarities. It has the advantage of being able to distinguish between out and out signals.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is a circuit diagram of an essential part of an embodiment of the invention, FIG. 3 is an explanatory diagram of a communication network, and FIG. 4 is a circuit diagram of an essential part of a conventional example. 1.2 is a detection element, Ll and L2 are lines, 11°12 is a photocoupler, 13.14 is a photodiode, 15.1
6 is a phototransistor.

Claims (1)

[Scope of Claims] In a device having a network control function, two detection elements (1, 2) each operating with a different polarity with respect to a line are provided, and the two detection elements (1, 2) When one of the detection elements (1) transitions from an operating state to a non-operation state and the other detection element (2) shifts from a non-operation state to an operation state,
Called party response and lockout, characterized in that it is detected as a called party response due to polarity reversal of the line, and is detected as a lockout when both of the two detection elements (1, 2) become inactive. Detection method.