JPS5827719B2 - System switching method for line switching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a system switching system for line switching equipment that performs switching of line switching equipment in a duplex configuration.

Line switching equipment including space switches and time switches in a time division switch is generally duplicated.

For example, as shown in FIG. 1, line switching devices 2a and 2b
are simultaneously controlled by the main controller 1 to perform time division switching operations, and the line selection device 3 selects the line and the line switching device 2.
The clock generating section 4 that supplies the clock CLK to the circuit switching devices 2a and 2b is shared.

In addition, in order to synchronize the address counters, etc. of the line switching devices 2a and 2b, a synchronization signal 5YNC is mutually supplied to the other device, thereby causing the line switching devices 2a and 2b to operate synchronously.

In the conventional example as described above, the duplex circuit switching devices 2a and 2b are completely synchronized, so that they can be switched at any time.

However, since the clock generating section 4 is shared, there is a drawback that a failure of the clock generating section 4 may cause the system to go down.

The present invention has improved the above-mentioned drawbacks.The purpose of the present invention is to improve reliability by duplicating the clock generating section, and to prevent synchronization of the line switching equipment due to the duplicating of the clock generating section. The aim is to prevent false information from being sent out.

Examples will be described in detail below.

FIG. 2 is a block diagram of an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts, and 4 a and 4 b are clock generators.

By providing the clock generators 4a, 4b corresponding to the line switching devices 2a + 2b in this way, even if the respective line switching devices 2a, 2b are controlled simultaneously by the main controller 1, the clock generators 4a, 4b , 4b is accumulated by an address counter or the like, resulting in an out-of-synchronization.

Therefore, when switching between the line switching devices 2a and 2b, the signal sent from the line selection device 3 to each line is temporarily stopped, and the signal transmission is resumed when the time relationship between the transmitted and received signals is normalized. It is.

FIG. 3 is a block diagram of the main parts of the line selection device, and Aa
, Ab, A1 to A6 are AND circuits, and Na.

Nb, N1 are NAND circuits, DEC is a decoder, MPX is a multiplexer, SB is a transmission buffer, FF is a flip-flop, ADR is a line address, RD is a received data, S
D is transmission data, WSTB is write strobe signal, S
T a and S T b are stop signals, and SEL is a selection signal.

If the line switching device 2a is the active system and the line switching device 2b is the backup system, the stop signal STa is jQ 11, and the selection signal S
EL becomes ``09+'', and the AND circuit Aa, A
I, A3 and A5 are opened.

Therefore, when the line address ADR from the line switching device 2a is applied to the decoder DEC and the multiplexer MPX, and the write strobe signal WSTB via the AND circuit Aa is applied to the decoder DEC via the AND circuit A5, the line address ADR The clock terminal C of the flip-flop FF of the transmission buffer SB corresponding to the line specified by
The decoder output is applied to the decoder output, the transmission data SD from the line switching device 2a is applied to the data terminal of the flip-flop FF and set, and the output is sent to the transmission line.

Also, the data on the receiving line is multiplexed in the multiplexer MPX according to the line address ADR, and the data is sent to the line switching device 2a.
, 2b as received data RD, time-division exchange is performed under the control of the main controller, and becomes transmitted data SD.

When switching to the standby circuit switching device 2b due to a failure in the circuit switching device 2a or a failure in the clock generation unit 4a,
AND circuit Aa with stop signals STa and STb as 1''
, Ab are closed and the sending of the write strobe signal WSTB is stopped.

Therefore, data transmission to the transmission line is stopped.

Next, the selection signal SEL is set to 1'', and the AND circuits AI and A3
゜A5 is closed, AND circuit A2. A4. A6 is opened, and the line address ADR from the line switching device 2b is sent to the decoder DEC and multiplexer MPX via the AND circuit A2.
The transmission data SD from the line switching device 2b, which has time-division exchanged the received data RD under the control of the main control device 1, is added to the transmission buffer SB.

However, since the write strobe signal WSTB is not output while the stop signal STb is "1", the transmission data SD is not set in the transmission buffer SB.

Stops when a relationship is established in which the received data RD multiplexed according to the line address ADR from the line switching device 2b and the transmitted data SD which is time-division exchanged and added to the transmission buffer SB are demultiplexed according to the line address ADR. The signal STb is set to uO+y, the write strobe signal WSTB is applied to the decoder DEC via the AND circuit A6, the line address ADR is decoded, the transmission data SD is set in the transmission buffer SH, and the data is transferred to the transmission line. Start sending.

As mentioned above, when switching between the line switching devices 2a and 2b, by temporarily stopping the transmission of data,
During this time, the relationship between the receiving and transmitting line addresses is established, so incorrect data will not be sent to the sending line at the time of switching, and, for example, control data for a terminal device may be sent to the wrong line, resulting in malfunction. This will prevent things like this from happening.

As explained above, in the present invention, by providing the clock generation units 4a and 4b in the line switching device 2ay2b with a duplex configuration, even if a failure occurs in one clock generation unit, the clock generation unit 2ay2b is provided with the clock generation units 4a and 4b. Time-division switching can be continued by the circuit switching device supplied with the clock, and the circuit configuration is simplified because there is no mutual transfer of synchronization signals between the circuit switching devices 2 a and 2 b.

Therefore, since the line switching device 2ay2b does not operate completely synchronously, it temporarily stops transmitting data during switching.
, Preventing the transmission of erroneous data due to an error in line specification during the transition of switching [~, since the time for establishing the line address relationship between the received data and the transmitted data can be estimated in advance, the elapsed time Afterwards, the transmission of the transmission data is restarted to complete the switching.

In this way, switching from the active system to the standby system of the line switching device can be performed without causing malfunctions to the terminal equipment or the like.

[Brief Description of the Drawings] Fig. 1 is a block diagram of a conventional time division switch, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a block diagram of main parts of a line selection device. . 1 is a main controller, 2a and 2b are line switching devices. 3 is a line selection device, 4a and 4b are clock generators, D
EC is a decoder, MPX is a multiplexer, ADR is a line address, RD is received data, SD is sent data, W
STB is a write strobe signal, STa and STb are stop signals, and SEL is a selection signal.

Claims (1)

[Claims] 1. A line switching device with a duplex configuration, a clock generator provided in each line switching device, a main control device that simultaneously controls time division switching operations in each line switching device, and a circuit between each of the line switching devices and the line. and a line selection device that performs multiplexing and demultiplexing between the lines, and when switching the line switching device, temporarily stops transmitting data, and then switches the line switching device from the active system to the protection system, A system switching method for a line switching device, characterized in that when a line address relationship between received data and transmitted data is established by the line switching device that changes from a standby system to a working system due to switching, transmission of transmission data is resumed. .