JP2669356B2 - PDS transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive double star (PDS) transmission system and, more particularly, to a transmission system for transmitting an alarm from a subscriber unit to an intra-office unit.

[0002]

2. Description of the Related Art Generally, a PDS for performing two-way communication
As shown in FIG. 2, the (passive double star) transmission system includes a star coupler 2, and an in-station device 3 is connected to the star coupler 2 via a transmission line 10. On the other hand, each of the star couplers 2 has a transmission path 11-1.
To 11-n, the first to the n-th subscriber devices 1-1 to 1-1
-N (n is a natural number) are connected.

In the illustrated PDS transmission system, the intra-station device 3 includes a transmission line 10, a star coupler 2, and a transmission line 11-1.
To 11-n to the first to n-th subscriber devices 1-1 to 1
-N performs bidirectional communication. At this time, the phases of the signals transmitted by the first to n-th subscriber units 1-1 to 1-n to the intra-station device 3 are managed by the intra-station device 3 so that the output signals of the subscriber devices do not collide with each other. Then, the signal transmission phase is instructed from the intra-station device 3 to the first to n-th subscriber devices 1-1 to 1-n.

Now, assume that a failure has occurred in the first subscriber device 1-1 such that a signal from the intra-station device 3 cannot be received. In this case, the first subscriber device 1-1 is the intra-station device 3
Cannot receive the signal transmission phase instruction from the mobile station, the signal transmission to the intra-station device 3 must be stopped, and as a result, the alarm transfer indicating the occurrence of the failure cannot be performed. Therefore, in the intra-office device 3, the input signal from the first subscriber device 1-1 is disconnected, but in the intra-office device 3, the first subscriber device 1-1 is disconnected.
It cannot be determined whether the signal has been lost due to the failure of the transmission line or the abnormality in the transmission line 11-1.

[0005]

As described above, in the conventional PDS transmission system, the output timing of the signal transmitted from each subscriber unit to the intra-office device is managed only by the intra-office device. When a trouble occurs in which the subscriber device cannot receive the signal from the intra-station device, each subscriber device cannot send the signal to the intra-station device, resulting in a problem that the alarm transfer cannot be performed. In addition, it is not possible to distinguish whether the input signal interruption has occurred due to a failure in the subscriber unit itself or a failure in the transmission line, and there is a problem that maintenance cannot be performed quickly.

It is an object of the present invention to provide a PDS transmission system capable of performing alarm transfer even when a reception failure occurs.

Another object of the present invention is to provide a PDS transmission system capable of distinguishing between a failure in a subscriber unit and a failure in a transmission line.

[0008]

According to the present invention, an in-station device and a plurality of subscriber devices are connected by a star coupler, and the in-station device and the plurality of subscriber devices are connected by signal distribution by the star coupler. In a PDS transmission system that performs bidirectional communication, each of the plurality of subscriber devices has different transmission timing for transmitting a transmission signal to the intra-station device, and the transmission timing is notified by the plurality of subscriber devices. A PDS transmission system characterized by having a notification means.

[0009] Then, a signal transmission phase instruction indicating the transmission timing is given from the intra-station device to the plurality of subscriber units.

The notifying means may include, for example, a phase information transmitting / receiving circuit provided in the plurality of subscriber units for transmitting the phase information indicating the transmission timing, and a connecting means for connecting the phase information transmitting / receiving circuits to each other. have.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Referring to FIG. 1, an illustrated PDS (passive double star) transmission system includes an intra-office device 3, a star coupler 2, and first to n-th subscriber devices 1-1 to 1-n.
(N is a natural number), a transmission line 10 connecting the in-station device 3 and one terminal of the star coupler 2, the other n terminals of the star coupler 2, and the first to n-th subscriber devices 1-1. ~ 1
and n transmission lines 11-1 to 11-n respectively connecting the first to n-th subscriber units 1-1 to 1-n.
Each having a receiving circuit 4 transmission phase information. The phase information transmission / reception circuits 4 in the first to n-th subscriber devices 1-1 to 1-n are connected to each other by connection lines 12.

In this PDS transmission system, the signal is distributed by the star coupler 2 and the first to n-th subscriber units 1-1 to 1-1.
1-n and the intra-station device 3 perform bidirectional communication. That is, the intra-station device 3 includes the transmission line 10, the star coupler 2, and the transmission line 1.
1 to n-th subscriber device 1 through 1 to 11-n
Bidirectional communication is performed with 1 to 1-n. During this two-way communication,
The phases of the signals transmitted by the first to n-th subscriber units 1-1 to 1-n to the intra-office device 3 are determined by the intra-station device 3 so that the output signals of the individual subscriber units do not collide with each other. 1 to n-th subscriber device 1-1 managed by the in-office device 3
The signal transmission phase is instructed to ~ 1-n.

The phase information transmitting / receiving circuit 4 in each of the first to n-th subscriber units 1-1 to 1-n converts the phase information of the signal output from each subscriber unit to the intra-office unit 3 into the other subscriber units. The transmission is performed to the device using the connection line 12, and the phase information of the signal output from the other subscriber device to the intra-office device 3 is received using the connection line 12. Thereby, the first to n-th subscriber devices 1-1
To 1-n is intra-station device 3 in apparatus other than the self apparatus throat phase
To know if you are sending a signal to.

Here, it is assumed that a failure has occurred in the first subscriber device 1-1 in which a signal from the intra-station device 3 cannot be received. The first subscriber device 1-1 uses the phase information transmission / reception circuit 4 in the first subscriber device 1-1 to transmit the second to n-th subscriber devices 1-2 to 1-1.
n receives the phase of the signal output to the intra-station device 3, so that the second to n-th subscriber units 1-2-1 -n have an empty area other than the phase output to the intra-station device 3. using,
The alarm generated in the own device is transferred to the intra-office device 3 without affecting the communication of the second to n-th subscriber devices 1-2 to 1-n.

As described above, when the first subscriber device 1-1 autonomously forwards the alarm to the intra-office device 3,
An identifier indicating that the information is an independent transfer is added to the alarm transfer information.

The intra-office device 3 receiving the alarm transfer information to which the identifier is added recognizes that a failure has occurred in the subscriber device 1-1.

[0018]

As described above, according to the present invention, since each subscriber unit is provided with a circuit for transmitting and receiving the phase of the signal output from the subscriber unit to the intra-station unit, the circuit is transmitted from the intra-station unit.
Even if a failure has occurred such that a signal cannot be received, an alarm can be transferred to the intra-office device without affecting other subscriber devices. In addition, this makes it possible to determine whether a fault that has occurred is a device fault or a transmission line fault, so that there is an effect that maintenance action can be quickly performed when a fault occurs.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing an example of a conventional PDS transmission system.

[Explanation of symbols]

 1-1 to 1-n Subscriber device 2 Star coupler 3 In-station device 4 Phase information transmission / reception circuit 10 Transmission line 11-1 to 11-n Transmission line

Claims (3)

(57) [Claims] 1. A PDS transmission system in which an intra-station device and a plurality of subscriber devices are connected by a star coupler, and the intra-station device and the plurality of subscriber devices perform bidirectional communication by signal distribution by the star coupler. Each of the plurality of subscriber devices has a different transmission timing for transmitting a transmission signal to the intra-station device, and has a notifying means for notifying the plurality of subscriber devices of the transmission timing. PDS transmission system. 2. The PDS system according to claim 1, wherein the in-station device gives a signal transmission phase instruction indicating the transmission timing to each of the plurality of subscriber devices. Transmission system. 3. The PDS transmission system according to claim 2, wherein said notifying means is provided in said plurality of subscriber units and transmits phase information indicating said transmission timing, and said phase information transmitting and receiving circuit; A PDS transmission system, comprising: connection means for mutually connecting transmission / reception circuits.