JPH0669944A - Drop/insert multiplex terminal station system for ring shape transmission line - Google Patents

Abstract

PURPOSE:To enhance the reliability of each channel by enabling the bypass of a transmission line in the opposite direction in the unit of channels when a fault takes place in the ring shape transmission line. CONSTITUTION:The system is provided with interruption detection circuits 3, 6 detecting an interference fault of transmission lines 1, 2, interruption signal insertion circuits 4, 5 inserting the detected interruption signal to auxiliary bits (e.g. bits c, d of an exchange signal in the case of, e.g. the 2M PCM) provided to each channel of a transmission signal of an opposite transmission line, an interruption signal detection circuit 8 detecting the interruption signal inserted to the auxiliary bits from the reception signal of a dropped channel and sending the detection signal to a drop/insert circuit 7, and the drop/insert circuit 7 accommodating a controller which branches the channel dropped/ inserted from the signal of the transmission lines 1, 2 to its own station and selects the opposite transmission line based on the interruption detection signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drop / insert multiple terminal device for a ring-shaped transmission line, and particularly to a 2 MHz P
The present invention relates to a ring-shaped transmission line drop / insert multiplex terminal device for a CM multiplex terminal device or the like.

[0002]

2. Description of the Related Art Conventionally, this kind of drop / insert multiplex terminal equipment for ring-shaped transmission lines is a PCM multiplex terminal equipment of about 30 channels, and a plurality of them are arranged in a ring-shaped transmission line to obtain multiplexed signals of the transmission line. From / to add / drop the local channel for each channel. In this way, the channels required between the terminal devices are configured when they are fixed. Further, with respect to the failure of the transmission path, a dual transmission path of working / spare is prepared, and when the failure is detected, the transmission side is switched to the protection side.

[0003]

As described above, in the conventional example, when a redundant configuration is adopted for a transmission line failure, a backup transmission line is required, and a switching unit is a transmission line unit and a channel unit is a failure unit. There is a problem that it cannot be switched.

[0004]

DISCLOSURE OF THE INVENTION A drop / insert multiplex terminal device for a ring-shaped transmission line according to the present invention comprises a disconnection detection circuit for detecting disconnection of a reception signal from one transmission line, and an output of the disconnection detection circuit. A disconnection signal insertion circuit for inserting a disconnection signal into a plurality of auxiliary signal bits in a channel unit arranged in a transmission signal to a transmission path in the opposite direction, and transmission / reception between the one transmission path and the transmission path in the opposite direction. A drop / insert circuit that switches the transmission path of a channel that passes or drops signals to each other channel by channel and switches to the transmission path of the opposite direction by a switching signal, and a digital signal of the channel that the drop / insert circuit drops A channel board for converting into a signal and a disconnection signal of the auxiliary signal bit is detected from the digital signal of the channel and the switching signal is output. And a signal detection circuit.

[0005]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

Received signals from the transmission lines 1 and 2 (for example, 2M
Transmission path disconnection detection circuits 3 and 6 for detecting disconnection of PCM signals) and channels arranged in transmission signals to the transmission paths 2 and 1 in opposite directions by disconnection signals output from the transmission path disconnection detection circuits 3 and 6. Multiple auxiliary signal bits per unit (eg 2M PC
In the case of M, the disconnection signal bit insertion circuit 4 for inverting (the c and d bits of the exchange signal are used) and each transmission / reception signal of the transmission line 1 and the transmission line 2 are thru or dropped in a channel unit and dropped. From the channel signal, a drop / insert circuit 7 including a controller that switches the channel transmission path to a transmission path in the opposite direction by a switching signal, a channel board 10 that converts the channel signal dropped by the drop / insert circuit 7 into a voice band signal, A disconnection signal detection circuit 8 that detects a disconnection signal of the auxiliary signal bit and outputs a switching signal to the controller of the drop / insert circuit.

Next, the operation of this device will be described. For example,
When the disconnection of the received signal from the transmission path 1 is detected by the transmission path disconnection detection circuit 3, this detection signal is input and the disconnection signal bit insertion circuit 4 inverts the auxiliary signal bit. This allows transmission line 2
In each terminal connected to, the disconnection signal detection circuit 8 of the corresponding channel detects this disconnection signal and drops the switching signal.
It is sent to the controller of the insert circuit 7. The drop / insert circuit switches the corresponding channel to the transmission path in the opposite direction to secure the detour.

[0008]

As described above, according to the present invention, when one transmission line is disconnected, the channel is switched to the transmission line in the opposite direction to secure the detour, so that the backup transmission line is not required and Since switching can be performed for each channel, there is an effect that a low-cost and highly reliable line can be secured.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

[Explanation of symbols]

 1, 2 Transmission line 3, 6 Break detection circuit 4, 5 Break signal bit insertion circuit 7, 13 Drop / insert circuit 8 Break signal detection circuit 9, 14 Common control unit 10, 15 channel board

Claims (1)

[Claims] 1. A plurality of disconnection detection circuits for detecting disconnection of a reception signal from one transmission path, and a plurality of disconnection signals output from the disconnection detection circuit for transmission signals to transmission paths in opposite directions. A disconnection signal insertion circuit to be inserted into the auxiliary signal bit of
A drop / insert circuit for passing or dropping each transmission / reception signal of the one transmission path and the transmission path of the opposite direction on a channel-by-channel basis and switching the transmission path of the channel to be switched to the transmission path in the opposite direction by a switching signal. A channel board for converting a digital signal of a channel dropped by the drop / insert circuit into a voice band signal, and a disconnection signal detection for detecting the disconnection signal of the auxiliary signal bit from the digital signal of the channel and outputting the switching signal A drop / insert multiplex terminal device for a ring-shaped transmission path, which is provided with a circuit.