JPS5827455A - Failure countermeasure system for button telephone set - Google Patents

Abstract

PURPOSE:To normally keep operation between a master device and other slave devices, by detecting a failure of transmission/reception function of a slave device of by the master device itself, and disconnecting a transmitter/receiver from a control line. CONSTITUTION:A control signal TxD from a master device is transmitted to a slave device designated with polling via a transmission section as a pulse signal. During the transmission, a reception section is stopped for the reception with an inhibition signal RTS but can receive a signal from the slave device with a photocoupler PC1 through the inversion of the signal RTS. The transmission/ reception circuit of the slave device makes signal transmission/reception to/ from the master device with photocouplers PC13 and PC14. A slave processor monitors an output signal IRQ of a photocoupler PC12 for transmission monitor and if a failure is detected in the said signal, it is discriminated as the failure of transmission/reception function. A signal EM is inverted and a transistor Q11 is turned off via the photocoupler PC11 to disconnect the transmission reception circuit from the control line.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a button telephone device that transmits and receives control signals between a main unit and a slave unit via a signal line, and is capable of detecting failures caused by failures in the transmitting and receiving functions of the slave unit. This concerns the countermeasure method.

Recently, in key telephone devices, multiple control signals are sent and received through a common signal line in order to reduce the number of core wires in the multicore cable that connects the main device and each slave device. , If a failure occurs in the control signal transmission/reception function of any handset, the handset will remain in the control signal transmission state, or the common signal may be interrupted due to a short circuit to the signal line, etc. This has the drawback that normal transmission and reception of control signals between the slave unit and the main unit via wire becomes impossible, and the function of the entire system is lost.

The purpose of the present invention is to fundamentally solve such drawbacks of the conventional technology, and when a failure occurs in the transmitting/receiving function of the handset side, the present invention detects this from itself and operates the transmitting/receiving circuit connected to the signal line. The present invention provides an extremely effective fault-proofing method for button-to-talk devices that prohibits the use of button-to-talk devices.

Hereinafter, the present invention will be explained in detail with reference to main circuit diagrams showing embodiments.

In the figure, the main unit 8U and the slave unit 8T are connected by a pair of signals 118Ll and SLm, through which control signals are transmitted and received between them. A coded pulse signal generated by intermittent DC current supplied to the main device from the 8Uif power supply +12V is used as a control signal.

In addition, when a plurality of slave units 8T are connected in parallel to the signal lines 8Lt and 8Ls, and the slave units 8T designated by the polling signal from 8U to the main unit sequentially transmit predetermined signals, A split transmission method was adopted, and the main unit 8U and each slave unit 8T were equipped with microprocessors such as CPUm and CPU5, and control signals were sent and received according to their control. ing.

The transmission section TX of 8U as the main device is composed of a constant current circuit consisting of a resistor R1, diodes Dl, Ds and a transistor Q1, and a drive circuit consisting of resistors R1-R4 and a transistor Qs, and a processor CPUm. When the transmission data TxD is generated in the form of a pulse, the transistor Ql is also turned on and off in accordance with the on/off of the transistor Q2, and a pulsed transmission signal having a peak value of 12V, which is a constant current value, is sent to the signal line 8Ll. Sent out.

On the other hand, the receiving section BX includes a voltage stabilizing circuit including resistors Re, Re, a transistor Q8, and a constant voltage diode ZDI, a resistor R9, and a diode Ds.

Consisting of a constant current circuit consisting of D4 and transistor Q4, a drive circuit consisting of resistors R8 to 'fLlO and transistor Qs, and a receiving circuit consisting of photocoupler PCI, diode D5 for blocking reverse current, and resistors R11 and R11l. However, due to the voltage stabilization circuit, the voltage is increased by +5
The current with a constant current value of V is the signal @8L of slave unit ST@
The transmission data Tx is supplied depending on the
While D is occurring, the inhibit signal RT8 turns off the transistor Qs and turns off the transistor Q4, so the receiving section RX does not operate.

On the other hand, in the slave unit ST, transistors Qll to Q
14, resistor Ra1~Ray, photocoupler PC11~
No. 201, a transmitter/receiver circuit TR consisting of diodes Dll, Dlm, and a constant voltage diode ZDII having a Zener voltage higher than 5 and lower than 12V is connected to the signal line SL.
1.8Ls, and correspondingly, the resistor Rs s~RB6, the photocoupler PCII-P
A drive circuit DR consisting of C14, transistor Qll, 16, and capacitor C1l is connected to the processor CPU.
5 and the transmitting/receiving circuit TR. Normally, the detection signal KM, which is inverted in response to the detection of a fault, turns on the transistor Ql11 and turns on the transistor Qu via the photocoupler PCII. , control faith! is connected to the transmitter/receiver circuit T8.

Therefore, the control signal having a peak value of 12V from the transmitter (IITX) passes through the transistor Q14 and the voltage regulator diode ZDII of the transmitter/receiver circuit TR, and passes through the photocoupler P.
Resistor 11i) Re in the drive circuit DB via Cx*f
This changes the ground side potential of the slave unit s, and this is given to the processor CPU 5 as a signal.
Control signal reception on the T side is performed.

When the transmission from the 8U side to the main device is completed, the prohibition signal RT
8 is inverted and the transistor Qi is turned on, the transistor Q4 is also turned on. In this state, the voltage of +5 V is applied to the signal line 8Ll via the photocoupler PCI and the diode Ds. When the processor CPU5 of the machine 8T generates the transmission output SO in the form of a pulse, the transistor Q16 turns on and off, and in order to turn on and off the transistor Q1m via the photocoupler PCl3, the resistor R14 outputs the signals l1IsLl,S.
The L islands are bridged, and a corresponding current is passed to the 7 Otocoupler PCI of the main unit KSU, converted into a change in the ground side potential of the resistor R1m, and then given to the processor CPU as received data RxD.

However, at this time, since the voltage between the signals @SLI and SLi is 5.times., the constant voltage diode ZDII is off, and the photocoupler PCl4 does not respond.

In addition, in response to the on/off tC of the transistor Q1s, the transistor Q1m is also turned on/off, and in synchronization with the on/off of the transistor Qls, a current is passed to the photocoupler PCIB, which is passed through the photocoupler PC1m to the resistor RIIO. When the terminal voltage changes, capacitor C
The signal is averaged by 1l, and then given to the processor CPU5 as the detection power IRQ for transmission from the slave ST side.

Therefore, the detection power IRQ always occurs during transmission from the handset 8T, and it is
If U5 monitors and detects IRQ does not occur even during transmission, even though it is not transmitting, detects IRQ
If Q occurs, short circuit or open circuit of transistor Qls, short circuit of constant voltage diode ZDII, photocoupler P
It automatically determines that a failure has occurred in the transmitting/receiving function due to an abnormality in Cta, inverts the detection signal EM, and switches on the transistor Q1s.
is turned off and transistor Q11 is also turned off, so that transmitting/receiving circuit TB- is disconnected from signal line 8Lt and its operation is prohibited.

Therefore, the signal lines 8Ll and SLs can be used normally between the slave unit ST and the main unit 8U where no fault occurs, and the functions of the entire system are maintained perfectly.

However, as long as it has a similar monitoring function, the configuration of each part may be determined depending on the type of control signal, and the present invention can be implemented in various forms.

As is clear from the above theory lI#c, according to the present invention,
Since a handset that has a problem with its transmitting/receiving function is automatically excluded from the common signal line, the functionality of the entire system is maintained completely except for the handset that has a problem, which is especially important in button telephone devices for various uses. You can get the following effect.

[Brief explanation of the drawing]

The figure is a main circuit diagram showing an embodiment of the present invention. K8U...Main unit, 8T...War/Slave unit, 8Lx, 8
Ls**s* signal line, CPUm, CPU5...e processor, TX...transmitter, RX...receiver, T
R...Intermediate reception circuit, DE'La*aa drive circuit, Q
x~Qs, Qzz-Qta #pot...transistor,
PCI, PCII-PCl3 clear...O photocoupler,
Dt-DIl, Dll, D12 a @ @ diode, ZDI, ZDII...e, constant voltage diode,
R1~R1g, Rat~Rsa*11 @
11 resistor, C11... Tube capacitor Patent applicant Tamura Electric Co., Ltd. Agent Masaki Yamakawa (and 1 other person)

Claims (1)

[Claims] In a button telephone device that transmits and receives control signals between a main device and a handset via a signal line, when a failure occurs in the transmission/reception function of the handset, this is detected by itself and connected to the signal line. A fault countermeasure method for a button telephone device is characterized in that the operation of transmitting and receiving circuits is prohibited.