JPH04240932A - Optical subscriber transmission system - Google Patents

Abstract

PURPOSE:To improve the reliability and to reduce the maintenance cost. CONSTITUTION:An optical multiplexer 4 installed in a center station 1 multiplexes plural subscriber signals and a specific frame synchronizing signal is inserted to the multiplexer frame of the optical multiplexer signal by each subscriber terminal equipment 3. An optical distributer 5 installed in a remote station 2 branches an optical multiplex signal sent from the center station 1 via an optical transmission line as it is and distributes it to each subscriber terminal equipment 3. An optical receiver 6 of each subscriber terminal equipment 3 detects a specific frame synchronizing signal of the subscriber terminal equipment 3 included in the optical multiplex signal and extracts only the subscriber signal addressed to the subscriber terminal equipment from the optical multiplex signal in response to the detection output.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical subscriber transmission system, and more particularly to an optical subscriber transmission system in which signals are transmitted between a center station and a plurality of subscriber terminals using the same optical multiplexed signal.

0002

2. Description of the Related Art FIG. 3 shows a conventional optical subscriber transmission system. The conventional optical subscriber transmission system consists of a center office (COT) 1, a remote station (RT) 2 connected to the center office 1 via an optical transmission line, and a plurality of subscriber terminals connected to the remote station 2. 3. In the conventional optical subscriber transmission system, the remote station 2 is provided with an active device 7, and the active device 7 terminates the optical multiplexed signal from the center station 1. More specifically, this active device 7 converts the optical multiplexed signal into an electrical signal, separates the converted electrical signal into electrical signals corresponding to each subscriber terminal 3, and then converts the electrical multiplexed signal into an electrical signal corresponding to each subscriber terminal 3. Convert the signal back into an optical signal,
This converted optical signal is sent to a plurality of subscriber terminals 3.

0003

[Problems to be Solved by the Invention] In this conventional optical subscriber transmission system, it is necessary to install an active device 7 at the remote station 2, which leads to a decrease in reliability and an increase in maintenance costs. There is a drawback.

An object of the present invention is to provide a highly reliable optical subscriber transmission system. Another object of the present invention is to provide an optical subscriber transmission system that can reduce maintenance costs.

[0005]

[Means for Solving the Problems] The optical subscriber transmission system according to the present invention includes a center station, a remote station connected to the center station via an optical transmission line, and a plurality of subscribers connected to the remote station. In the optical subscriber transmission system having terminals, the center station includes an optical multiplexing device that multiplexes a plurality of subscriber signals, and a multiplex frame of the optical multiplexed signal output from the optical multiplexing device. and insertion means for inserting different frame synchronization signals corresponding to the plurality of subscriber terminals, and the remote station receives an optical multiplexed signal transmitted from the center station via the optical transmission line. an optical distributor that distributes to each of the plurality of subscriber terminals;
Each of the plurality of subscriber terminals receives an optical multiplexed signal from the optical splitter and detects only a frame synchronization signal specific to the subscriber terminal from the received optical multiplexed signal; It is characterized by comprising information extraction means for extracting only the subscriber signal addressed to the subscriber terminal from the optical multiplexed signal in response to the detection output of the detection means.

[0006]

[Operation] Signal transmission between the center station and a plurality of subscriber terminals is performed using the same optical multiplexed signal.

[0007]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, the optical subscriber transmission system according to an embodiment of the present invention includes a center office (COT) 1 and a remote station (COT) connected to the center office 1 via an optical transmission line.
RT) 2 and a plurality of subscriber terminals 3 connected to the remote station 2.

[0008] The center station 1 is equipped with an optical multiplexer 4 for multiplexing a plurality of subscriber signals. FIG. 2 shows the structure of a multiplexed frame of an optical multiplexed signal output from the optical multiplexer 4. As shown in FIG. 2, a frame synchronization signal unique to each subscriber terminal 3 is inserted into the multiplex frame of the optical multiplex signal.

[0009] An optical distributor 5 is installed in the remote station 2. The optical distributor 5 branches the optical multiplexed signal sent from the center station 1 via the optical transmission line as it is and distributes it to each subscriber terminal 3.

Each subscriber terminal 3 has an optical receiver 6 . The optical receiving device 6 detects a frame synchronization signal unique to the subscriber terminal 3 included in the optical multiplexed signal, as shown in FIG. Only the subscriber signal addressed to the subscriber terminal is extracted.

[0011]

Effects of the Invention As explained above, the present invention enables remote communication by inserting unique frame synchronization signals corresponding to each subscriber terminal into multiplexed frames constituting an optical multiplexed signal at the center station. By distributing the optical multiplexed signal from the center station directly to each subscriber terminal using an optical splitter, without separating and converting it into optical signals for each subscriber terminal at the station, reliability of the line is ensured. This has the effect of reducing maintenance costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical subscriber transmission system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a multiplexed frame structure used in the present invention.

FIG. 3 is a block diagram showing the configuration of a conventional optical subscriber transmission system.

[Explanation of symbols]

1 Center station (COT) 2 Remote station (RT) 3 Subscriber terminal 4 Optical multiplexer 5. Optical distributor 6 Optical receiver

Claims (1)

[Claims] Claim 1. An optical subscriber transmission system comprising a center station, a remote station connected to the center station via an optical transmission line, and a plurality of subscriber terminals connected to the remote station, wherein the center The station includes an optical multiplexing device that multiplexes a plurality of subscriber signals, and a multiplexed frame of the optical multiplexed signal output from the optical multiplexing device, and a different frame corresponding to the plurality of subscriber terminals. and an insertion means for inserting a synchronization signal, and the remote station is an optical distributor that distributes the optical multiplexed signal transmitted from the center station via the optical transmission line to the plurality of subscriber terminals, respectively. each of the plurality of subscriber terminals receives an optical multiplexed signal from the optical splitter, and detects only a frame synchronization signal unique to the subscriber terminal from the received optical multiplexed signal. and information extraction means for extracting only the subscriber signal addressed to the subscriber terminal from the optical multiplexed signal in response to the detection output of the detection means.