JPH0374976B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a line control method for a communication system in which communication lines are dual system.

[Conventional technology]

FIG. 3 is a diagram showing a conventional duplex communication line control device. If the duplexed communication systems are called 1 system and 2 systems, respectively, the received signals of the 1 system and 2 systems in the figure are inputted from input terminals 100 and 101, respectively, and are sent to the receiver 10.
2, 103 to demodulators 107a, 107b, and the demodulated signals are sent to a serial/parallel signal converter (hereinafter referred to as an S/P converter) 10.
9a and 109b, and this parallel data is sent to the transmission/reception control unit 11.
0 and S/P converters 109a, 109b to 2-port memories 300, 301 that are readable and writable. On the other hand, 2 port memory 300, 30
The transmission data of 1 system and 2 systems respectively written to 1 are converted into serial signals by S/P converters 109a and 109b, and then sent to modulators 111a and 1.
The signal is modulated by the driver 11b, and the driver 112, 11
3 to the respective output terminals 114, 115
sent to.

Next, operations will be described when the communication lines of both systems 1 and 2 are normal and when a problem such as disconnection occurs in the communication line of either system.

If the lines of both systems are normal, the transmission/reception control unit 1
10 is a 2-port memory 300, 30 during transmission.
S/P converters 109a, 109b, modulators 111a, 111 of both systems
b. transmitting signals through drivers 112 and 113; Also, at the time of reception, the receivers 102, 10
3. Either of the contents written in the 2-port memory through the demodulators 107a, 107b and the S/P converters 109a, 109b is received data.

If there is an abnormality in the communication circuit of either system, when transmitting, the signal is sent to both systems in the same way as when both systems are normal, and when receiving, the signal is received only from the normal system, so the signal is transmitted from the normal system. The contents written in the port memory are the received data.

[Problem that the invention seeks to solve]

Conventional redundant communication line control equipment is equipped with a modulator, demodulator, and S/P converter for each communication circuit as described above, so the number of parts increases, and the reliability of the control equipment cannot be measured using MTBF as a measure. When considered, there were problems such as low reliability, large size, and high cost.

This invention was made to eliminate the above-mentioned problems, and an object of the present invention is to provide a duplex communication line control device that has a small number of parts, is highly reliable, is small in size, and is inexpensive.

[Means for solving problems]

The duplex communication line control device according to the present invention is provided with a receiver selector that selects and inputs the output signal of the receiver of both systems and the carrier signal to a demodulator and a carrier disconnection detector in the path of the received signal, and transmits the signal. The signal path is configured to simultaneously output the output signal of the modulator to both drivers.

[Effect]

In the receiver selector and carrier disconnection detector of the present invention, the transmission/reception control section selects the output of the receiver of the system in which the carrier exists, and inputs it to the demodulator, so that the demodulator can be used in common for both systems. Furthermore, the modulator can be shared by both systems, and the S/P converter can also be shared by both systems.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, received signals from the duplexed communication lines are input to input terminals 100 and 101, respectively, and passed through receivers 102 and 103 to a receiver selector 104 and carrier detectors 105 and 10.
6, and the outputs of carrier detectors 105 and 106 are also input to receiver selector 104.
The receiver selector 104 sends the received signal and carrier signal of the system designated by the system selection signal 117 from the transmission/reception control unit 110 to the demodulator 107 and the carrier signal, respectively.
The signal is sent to the carrier disconnection detector 108. The signal demodulated by the demodulator 107 is converted into parallel data via the S/P converter 108 and sent to the transmission/reception control section 110. The carrier interruption detector 108 outputs a carrier interruption detection signal 116 when there is no carrier for a certain period of time.
is sent to the transmission/reception control section. On the other hand, the transmitted data is S/
After being converted into serial data by the P converter 109 and modulated by the modulator 111, the drivers 112 and 11
3 simultaneously. Reference numerals 114 and 115 are output terminals connected to the duplex communication lines, respectively. FIG. 2 is a diagram showing the internal structure of the transmission/reception control section 110, in which 200 is a CPU, 201 is a RAM for storing data, 202 is a ROM in which control means of this control device is stored, and 203 is a counter for sending signals. 204 is an output device that outputs a signal from the transmission/reception control unit 110 to other parts of this device; 205 is a timer that generates a waiting state time for reception from the hand station; 205 is an output device that outputs a signal from other parts of this device to the transmission/reception control unit 110 This is an input device that inputs signals. Note that when the device shown in FIG. 1 is a transmitting station, there is a receiving station with the same configuration as that shown in FIG. 1 across the duplicated communication line.

Next, (1) when both systems of the duplicated communication line (referred to as 1 system and 2 systems, respectively) are normal, and (2) when there is an abnormality such as a disconnection in either system. The operation will be explained.

(1) When both systems are normal...The transmission control unit 110 of the transmitting station controls the drivers 112 and 11 for both systems 1 and 2.
3 sends signals to both communication lines through output terminals 114 and 115. At this time, since the lines of both systems are normal, the receiving station located at the end of the communication line accurately receives the signal from the transmitting station from either receiver 102 or 103 selected at that time, so both systems A signal reception confirmation signal is sent to the originating station through the line. Since the signal reception confirmation signal arrives at the input terminals 100 and 101 at the transmitting station, the transmitting station can receive the signal reception confirmation signal from the receiving station from one of the receivers 102 and 103 selected at that time.

(2) If there is an abnormality in either system...Now, 1
Assume that there is an abnormality in the system. The transmitting station sends a signal to the communication line through both drivers 112 and 113, selects one receiver system, and waits for a signal reception confirmation signal from the receiving station. If the receiving station had selected one system of receiver at this time, it would not be able to receive the transmission from the transmitting station at this time, so it would not transmit a signal reception confirmation signal to the transmitting station. Therefore, the transmitting/receiving control unit 110 of both the transmitting station and the receiving station uses the carrier disconnection detector 1 to detect that there is no carrier in the currently selected receiver.
08, the receiver selector 10
By outputting the system selection signal 117 to the receiver 4, it is instructed to receive signals from the two systems of receivers. In this way, if the transmitting station does not receive a signal reception confirmation signal from the receiving station for a certain period of time, it selects another receiver system, transmits the signal, and waits for a signal reception confirmation signal from the receiving station. If the transmitting station repeats this operation for a certain period of time until the receiving station's carrier disconnection detector 108 detects that there is no carrier in one system, both the transmitting station and the receiving station will select the normal receiver of the two systems. Therefore, communication is possible even if there is an abnormality in one system.

Similarly, when there is an abnormality in two systems, the receiver of one system is selected at this time.
Can make phone calls.

In the above embodiments, either baseband modulation or broadband modulation may be used, and the transmission method may be either full-duplex or half-duplex.
In short, in the present invention, the receiver selector selects and outputs the received signals of both systems and their carrier signals to the demodulator and carrier disconnection detector, respectively, and the output of the modulator passes through the drivers of both systems to communicate the signals of both systems. If it is configured to have a function of outputting a signal to a line, all the same effects as the present embodiment shown in FIG. 1 can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, in a duplex communication system, one modulator, one demodulator, and one S/P converter can be used in common for both systems, so that the number of parts is reduced. It has the advantage of being able to reduce costs, being highly reliable, and having a small size and low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a duplex communication circuit control device according to the present invention, FIG. 2 is a block diagram showing a detailed configuration of the transmission/reception control section in FIG. 1, and FIG. FIG. 1 is a block diagram showing the configuration of this type of device. 102 and 103 are receivers, 104 is a receiver selector, 105 and 106 are carrier detectors, and 10
7 is a demodulator, 108 is a carrier disconnection detector, 109
is an S/P converter, 110 is a transmission/reception control unit, 111
is a modulator, and 112 and 113 are drivers. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A duplex communication line control device in a communication system equipped with two communication lines, including a demodulator that demodulates signals flowing through each of the two communication lines, and a demodulator that demodulates signals flowing through each of the two communication lines, and a demodulator that demodulates signals flowing through each of the two communication lines. A modulator for modulation is common to each system, while two receivers capture signals flowing through each of the two communication lines, and a carrier flowing through the communication line of each system is detected from the output of each receiver. Two carrier detectors are provided to make the system redundant, and one of the systems is selected according to an instruction from the transmission/reception control unit based on the output of the carrier disconnection detector, and each of the selected systems is A duplex communication line control device comprising a receiver selector that outputs an output of a receiver to the demodulator and outputs an output of a selected carrier detector to the carrier disconnection detector.