JPH0236646A - Runaway prevention circuit for decentralized interphone system - Google Patents

Abstract

PURPOSE:To prevent the runaway of the title system and to eliminate the system-down by providing a transmission time check timer operated when a signal channel is closed due to faulty communication of the present station and stopping the erroneous transmission immediately after the transmission time check timer is activated. CONSTITUTION:When a noise exists in a program of the present station and a jamming less than, e.g., 147sec is sent through a signal channel from a transmission circuit 3, an overflow signal is outputted from an overflow timer 6 to a control circuit 2 in 147.5m sec and user terminal equipments TE1-TE12 are set to the initial state. When no overflow signal is outputted and a jamming over 147sec is sent to the signal channel, a clear signal is sent to the control circuit 2 from a signal channel monitoring timer 7 independently of the present station or other station to interrupt runaway. Thus, the system-down relating to the signal channel is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a runaway prevention circuit for a distributed intercom device, and more particularly to a runaway prevention circuit for a distributed intercom device having a signal channel.

[Prior Art] As shown in FIG. 4, a conventional distributed intercom device has a user terminal TEn (n is 1.2, and for the sake of explanation, n=1).
Set it to 2. ) is connected to the intercom exchange EX in a bus format. The user terminal TEn consists of a telephone terminal and a non-telephone terminal, and the telephone terminal is connected to the intercom exchange E.
X and a digital intercom interface. Non-telephone terminals include facsimiles, data terminals, etc.

User terminals TE, ~TE, 2 and intercom exchange E
X is connected with digital path line 1. Digital path line 1 is signal channel 1 channel and user terminal TE engineering ~
It is configured with a number of speech channels suitable for the traffic of TE1□, for example, 6 channels. The signal channel is the upstream signal of intercom exchange EX and the intercom exchange E.
It is used for transmitting downlink signals from X to user terminals TE1 to TE1□.

The user terminals TE1 to TE1□ are composed of a control circuit 2, a transmitting circuit 3, a receiving circuit 4, a communication circuit 5, and an overflow timer 6, as shown in FIG. The upstream signal sent from the transmission circuit 3 to the signal channel of the digital path line 1 via the cable driver 3a is sent to the intercom exchange EX according to a predetermined protocol. The downlink signal sent from the intercom exchange EX to the user terminal TEn is input to the receiving circuit 4 via the signal channel of the digital path line 1 and the cable receiver 4a. The control circuit 2 transmits and receives uplink and downlink signals to control the communication circuit 5. Note that the receiving circuit 4 can receive the upstream signal sent from the transmitting circuit 3 and monitor it with the monitor 4b. Note that the signal channel is used for transmitting uplink and downlink signals (also referred to as control signals and including data).

In the distributed intercom device having the above configuration, a response to a short signal from the user terminal TE1 can be monitored by a maintenance command using a down signal from the intercom exchange EX, and if necessary, the user terminal TE1 can be initialized.

User terminals TE1 to TE1. The processing of the control circuit 2 includes control of the control signal and data transmission circuit 3 and reception circuit 4.
control, control of the audio signal transmitting/receiving circuit 5, accompanying internal processing, and application of a clear signal to the overflow timer circuit 6.The maximum value of the total time of these series of processes is expressed as . When the overflow time of is expressed as T, it is set so that T>t. The overflow timer circuit 6 initializes the overflow time by applying a clear signal from the control circuit 2 within the time of the set quantum at the time of overflow, and restarts the overflow time starting from the time when the clear signal is applied. If no clear signal is applied during T, the control circuit 2 is configured to send out a reset signal. Therefore, in a normal operating state, the maximum time t required for a series of processing by the control circuit 2 is shorter than rfJT at the time of overflow of the overflow timer circuit 6, so that the control circuit 1 reset signal is not applied.

If the control circuit is unable to operate normally due to runaway or the like, the clear signal is no longer applied to the overflow timer circuit 6, and a clear signal is sent from the overflow timer 4 to the control circuit 2 after a certain period of time. As a result, the control circuit 2 is initialized by operating an emergency circuit (not shown), and returns to a normal state.

This series of procedures related to abnormality processing is also used for initialization processing of the entire system in the distributed intercom device. Any user terminal T among the plurality of user terminals TEn connected by the digital path line 1
A control signal or data is sent to the user terminal T E
It is provided with a function that can send data longer than the overflow time T of the overflow timer circuit 6 of n, and sends out data as necessary. As a result, the control circuit 2 of the other user terminal TEn continues to receive the signal input from the receiving circuit 4, and cannot apply a clear signal to the overflow timer circuit 6. Therefore, each user terminal TEn
The control circuit 2 is given an overflow signal from the overflow timer circuit 6, and the entire system is initialized.

[Problems to be Solved by the Invention] In the runaway prevention circuit of the distributed intercom device having the above configuration, an abnormality is detected in the signal channel of the digital path line 1 by an upstream signal defined in a predetermined protocol from the transmission circuit 3 of the user terminal TEn in the runaway state. When a long signal is sent to the control port R2 and a clear signal is sent from the control circuit 2 to the overflow timer 6, the overflow timer 6 is in a state in which it does not send an overflow signal to the control port R2. For this reason, the signal channel of the digital path line 1 is not only blocked by abnormal signals and the system goes down, but also the user terminal TEn that is transmitting abnormally cannot be identified, which is a problem that must be solved.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and is provided with a transmission time check timer that operates when the signal channel is blocked due to abnormal communication of the own station, and immediately stops abnormal transmission when the transmission time check timer operates. An object of the present invention is to provide a runaway prevention circuit for a distributed intercom device that can stop the operation.

[Means for Solving the Problems] A runaway prevention circuit for a distributed intercom device according to the present invention includes an intercom exchange, an intercom terminal connected to the intercom exchange via a transmission path consisting of a signal channel and a speech channel in a bus format. A distributed intercom device comprising: a control circuit provided in the intercom terminal; and an overflow timer that outputs an overflow signal to the control circuit to interrupt runaway of the program when the control circuit is not cleared by a clear signal of the control circuit. , a signal channel monitoring timer that monitors the time during which the signal channel is in use and is blocked, and outputs an aflation signal to the control circuit to interrupt program runaway when the blockage continues for a predetermined period of time or more. do.

[Embodiment] Hereinafter, an embodiment of the dash prevention circuit of the distributed intercom device according to the present invention will be described with reference to the drawings.

In FIG. 1, TE is a user terminal.

User terminal TE1 (other users are using terminals TE2 to TE, □
) are connected to a digital path line 1 consisting of one signal channel and six communication channels in the form of a bus as shown in FIG. The user terminal TE engineer has control circuit 2,
Transmission circuit 3, reception circuit 4, telephone communication circuit 5. It consists of an overflow timer 6 and a signal channel monitoring timer 7.

The control circuit 2 controls the transmission circuit 3 so that the control signal sent from the transmission circuit 3 to the signal channel of the digital path line 1 via the cable driver 3a follows a predetermined protocol. It also processes control signals input to the receiving circuit 4 via the cable receiver 4a via the signal channel of the digital path line 1.

The communication circuit 5 is controlled by the control circuit 2 in accordance with control signals sent and received by the transmitting circuit 3 and the receiving circuit 4 so that a communication channel is formed between the user terminals TE2 to TE, 2.

The overflow timer 6 is set to 0 to 31b as shown in FIG.
The clock pulse generator 8 is connected to the terminal T by the timer in the IT configuration.
A clock pulse φ of 0.3 μs is input to 1. Count. During normal operation, a clear signal sent from the control circuit 2 to the terminal T2 returns to O by executing a clear program (not shown) that starts every 48 m5. When the clear program is not executed, 491520 clock pulses are counted and the terminal T is counted every 147.5 mS.
, sends a buffer flow signal to the control circuit 2. Upon receiving the overflow signal, the control circuit 2 activates a built-in emergency circuit (not shown) and performs controls such as disconnecting the connected communication path in a predetermined order.

A signal channel monitoring timer 7 monitors the signal channel. When there is a signal on the signal channel, the output side of monitor 4b becomes H.
level. When the output side of the monitor 4b becomes H level, the terminal T2 of the signal channel monitoring timer 7 becomes H level, and the clock pulse generation circuit 8 counts the 3 mS clock pulse φ input to the terminal T1 as shown in FIG. . When the control signal being sent and received on the signal channel disappears, the terminal T2 goes to L level and the signal channel monitoring timer 7 returns to O. When the count value reaches 491520 while terminal T2 remains at H level, terminal T2 is reset every 147 seconds.
3 outputs an after-flare signal to the control circuit 2. The control circuit 2 to which the after-flare signal is input operates in the same manner as in the case of an overflow signal, and interrupts the runaway of the program.

[Operation of the invention] When the signal channel is empty, the intercom exchange EX
When a maintenance command is sent to the user terminal TE, ~TE1□, a response using an uplink signal is sent to the intercom exchange, and if necessary, the user terminal TE, ~TE1□
E1. can be initialized using maintenance commands.

When there is a jam in the program at the local station and a jam of less than 147 seconds is sent from the transmitting circuit 3 to the signal channel, the overflow timer 6 outputs a buffer flow number a from the control circuit 2 in 147.5 mS, and the user The terminals TE-TE1□ are initialized.

1) If the overflow signal is not output and a jam of 147 seconds or more is sent to the signal channel, a clear signal is sent from the signal channel monitoring timer 7 to the control circuit 2, regardless of whether it is the own station or another station, to prevent runaway. Interrupt.

In the above embodiment, the output of the monitor 4b is made indiscriminate, but it may be configured such that priority is given to the output of the own station, and the output is not activated when another station runs out of control. The number of communication channels, the time of the overflow timer and the signal channel monitoring timer are not limited to the above embodiments.

[Effects of the Invention] A runaway prevention circuit for a distributed intercom device according to the present invention includes an intercom exchange and an ink-phone terminal connected to the intercom exchange via a transmission path consisting of a signal channel and a speech channel in a bus format. a distributed intercom device, comprising: a control circuit provided in the intercom terminal; and an overflow timer that outputs an overflow signal to the control circuit to interrupt runaway of the program when not cleared by a clear signal of the $ control circuit;
and a signal channel monitoring timer that monitors the time during which the signal channel is in use and is blocked, and outputs an aflation signal to the control circuit to interrupt program runaway when the blockage continues for a predetermined period of time or more. Therefore, the feature is that the emergency circuit can be activated for rAg of the signal channel. Therefore, it is possible to prevent system failure related to signal channels.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a runaway prevention circuit for a distributed intercom device according to the present invention, and FIGS. 2 and 3 are configuration diagrams of an overflow timer and a signal channel monitoring timer according to FIG. FIG. 4 is a relay system diagram of a distributed intercom device, and FIG. 5 is a block diagram of a runaway prevention circuit of a conventional distributed intercom device. 1... Digital path line 2... Control circuit 6... Overflow timer 7... Signal channel monitoring timer EX...
Intercom exchange TEn...user terminal

Claims (1)

[Claims] A distributed intercom device comprising an intercom exchange and an intercom terminal connected to the intercom exchange via a transmission path consisting of a signal channel and a speech channel in a bus format, comprising: a control circuit provided in the intercom terminal; an overflow timer that outputs an overflow signal to the control circuit to interrupt program runaway when the circuit is not cleared by a clear signal; and an overflow timer that monitors the time that the signal channel is in use and is blocked, and detects the blockage for a predetermined period of time or more. A runaway prevention circuit for a distributed intercom device, comprising: a signal channel monitoring timer that outputs an afterrun signal to the control circuit to interrupt runaway of the program when the program continues to run out of control.