JPS5863259A - Spare system for subscriber circuit - Google Patents

Abstract

PURPOSE:To maintain the service without giving any effect of the exchange process and to realize remote maintenance with improved performance, by providing a lead-in relay and a spare subscriber circuit to each subscriber, and setting a branching/inserting circuit at the channel side. CONSTITUTION:A connection is given to a spare subscriber circuit LCS through the break contacts of lead-in relays r1-rn of subscriber circuits LC1-LCn. The PCM signal of the circuit LCS is also connected to a branching circuit DRP and an inserting circuit INS. For instance, if the circuit LC1 has a fualt, a control circuit CONTROL drives the relay r1 to lead the subscriber into the circuit LCS. At the same time, a command is given to the circuits DRP and INS so that the time division multiplication and multiplex separation are applied to the PCM signal of the spare subscriber circuit in place of the circuit LC1 at a time slot t1. As a result, the signal of the LCS instead of LC1 is multiplexed to the PCM multiplex signal which is given to a time division channel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to digital telephone exchanges, and more particularly to subscriber circuit protection schemes.

Compared to electronic exchanges using conventional electromagnetic communication paths, digital telephone exchanges have a much larger portion of their hardware that is occupied by subscriber circuits.

Therefore, improving the maintainability of this part is important for operational management of the exchange system. Further, digital telephone exchanges are often installed as remote stations due to their affinity with PCM lines, and in this case, maintenance is usually unmanned and requires remote maintenance from the master station.

From the above points, improving the failure maintainability of subscriber circuits is extremely important in ensuring continuity of service to subscribers.

The purpose of the present invention is to provide a pull-in relay and a backup subscriber circuit for each subscriber, and when a failure occurs in the subscriber circuit during operation, the pull-in relay connects the subscriber to the backup subscriber circuit, and on the communication path side, a digital circuit is used to branch out. By installing an insertion circuit, interlocking time slot assignment with the pull-in operation, allocating it to the backup subscriber circuit side, and providing a control circuit that automates the series of switching processes described above, service can be continued without affecting the switching process. K provides a subscriber circuit backup system that enables remote unattended maintenance.

According to the present invention, when a backup subscriber circuit is set up for a subscriber circuit of N lines (N=an integer of 2 or more), a switching relay having a function of connecting the subscriber circuit to the N subscriber circuits is connected to the subscriber circuit. A time slot is provided for each circuit, and between the input/output PCM signal of the subscriber circuit and the time-division communication path, the input/output PCM signal of the standby subscriber circuit is assigned to any one of the N subscriber circuits. By providing branching and insertion circuits in the subscriber circuit, a subscriber circuit backup system with excellent maintainability and service continuity can be constructed.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. N
The subscriber SUB of the line is the backup switching relay r1~rnet
It is connected to subscriber circuits LC1 to LCn via the subscriber circuits LC1 to LCn. The subscriber circuits LC1 to LCn are a subscriber interface circuit 5LIC consisting of a power supply circuit, a calling signal circuit, an on-hook/off-hook detection circuit, a 2M/481 conversion circuit, and a test access circuit, and a PCM modulation/demodulation circuit for voice signals C and OD.
Consists of EC.

These subscriber circuits are assigned time slots (tl-tn) on the PCM multiplex line and are connected to the time division communication path via the branch circuit DRB insertion circuit IN5t.

The backup subscriber circuits LCsK are subscriber circuits LC1 to LCn.
A connection is made through the break contact H of the pull-in relay rl-rfi. This backup subscriber circuit LC.

The PCM signals of are also connected to the branch circuit insertion circuits DRP and INS. For example, when the subscriber circuit LCs is in failure, the control circuit C0NTR0L drives the switching relay txt to pull the subscriber into the backup subscriber circuit LC@. At the same time, branch circuit DRP
The insertion circuit INS is instructed to time-division multiplex and demultiplex the PCM signal of the backup subscriber circuit instead of the subscriber circuit LCI at time slot tl. As a result, the second
As shown in the figure, signals from the standby subscriber circuit LC instead of the subscriber circuit LC1 are multiplexed into the PCM multiplexed signal to the time-division communication path.

For example, the insertion circuit INS is composed of a so-called 2→1 selector, and it is specified for each time slot whether to select a signal from a backup subscriber circuit or a general subscriber circuit. The branch circuit, on the other hand, is composed of a gate circuit that switches the signal from the time-division communication path between the general subscriber circuit and the standby subscriber circuit for each time slot.

Switching relays and standby subscriber circuits can also be used to perform subscriber testing. In other words, this function can also be used to switch and identify whether the fault is on the line side or on the subscriber circuit.

By using this format, after detecting the faulty subscriber circuit, it is switched to the spare subscriber circuit.In the exchange process, the time slot assignment is the same as that of the faulty subscriber, so the implementation number is the same and there is no effect at all. . Furthermore, even in a remote station, this can be done automatically by controlling from the master station side through the control circuit C0NTR0Lt, thereby preventing interruption of service for faulty subscribers for repair.

As explained above, in the present invention, a pull-in relay and a backup subscriber circuit are provided for each subscriber, and when a failure occurs in the subscriber circuit during operation, the pull-in relay is used to pull the subscriber circuit into the backup subscriber circuit. By installing a digital add/drop circuit, linking the time slot assignment to the pull-in operation, and assigning it to the backup subscriber circuit side, service can be continued without any impact on the withdrawal or replacement process, and maintainability is improved. This has the effect of enabling remote unmanned maintenance.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 12 (
A) and CB) are timing diagrams showing an example of time slot assignment. SUB...Subscriber, LCI~LCn...
・Subscriber circuit, LC,... Backup subscriber circuit,
5LIC...Subscriber interface circuit, C0
DEC...2...PCM modulation/demodulation circuit, INS...
...insertion circuit, DRP...branch circuit, rl~r
n...Spare switching relay, -CONTROL・
...Control circuit.

Claims (1)

[Claims] N (N is an integer of 2 or more) lines, if a backup subscriber circuit is set up for the subscriber circuit, a switching relay having the function of pulling the N line into the backup subscriber circuit is installed for each subscriber circuit as described above. Branching and inserting the input/output PCM signal of the standby subscriber circuit between the input/output PCM signal of the subscriber circuit and the time-division communication path into a time slot assigned to any one of the N subscriber circuits. A subscriber circuit protection system in a digital telephone exchange characterized by providing a circuit.