JP2892366B2 - Remote power control unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a communication control device connected to a communication network, and particularly to a control device for a terminal device.

(Prior Art) In general, a connection configuration of a communication system that connects a host device and a terminal device is shown in FIG. In the figure, reference numeral 1 denotes a communication control device (hereinafter, referred to as DTE) on the host device side;
Is a line termination unit (hereinafter referred to as DSU), and 3 is a DDX (Digi
tal Data Exchange) network, 4 is DSU, 5 is DT on the terminal device side
E. Line interface between DSU4 and DTE5 is fifth
The T (transmission) line, R
These are called (receive) lines, C (control) lines, I (indication) lines, and S (signal element timing) lines. Further, the DTE 5 on the terminal device side is configured by a remote power control device (hereinafter referred to as RPC) 5a which is a control device of the terminal device, and a master device 5b including a power source which is remotely controlled.
C5a is connected to the line interface of DSU4.

Under such a configuration, conventionally, a message transmitted from DTE1 on the higher-level device side to the terminal device side via DSU2, DDX network 3, DSU4 is received by DTE5, and DTE5 transmits the response to DSU4, DDX5. network
3. The data was returned to DTE1 on the host device side via DSU2. DTE5
Is activated by a message from the host device and performs a determined process. Here, when the DDX network 3 on the DTE 5 side fails, the I line shown in FIG. 5 is turned off, and the DTE 5 detects the failure state of the DDX network 3 by detecting this. In addition, when the I line is restored to ON, the restoration state of the DDX network 3 is recognized. When the I line turns on, DTE5 becomes DDX
In order to establish a link with the network 3, a SABM (asynchronous equilibrium mode setting) command is sent to the DSU 4, and an unnumbered acknowledgment (UA) response from the exchange on the DTE 5 side of the DDX network 3 is sent to the DSU 4 in response to the SABM command. By receiving more
The DTE 5 has established a link with the DDX network 3 and is in a state of waiting for a message from a higher-level device. Then, when the RPC 5a receives a specific message from the higher-level device, the RPC 5a turns on the power of the parent device 5b and starts up the entire DTE 5 system. RP
C5a is powered on 24 hours a day, and a link is always established with the DDX network 3. Therefore, the RPC 5a is normally
Waiting for a specific message from a.

(Problems to be Solved by the Invention) However, in the conventional method described above, DS is required for maintenance.
When the power supply of U4 is turned on and off, or when an instantaneous interruption of the AC100V line of DSU4 occurs, the connection with the DDX network 3 becomes defective, and the interface between DSU4 and DTE5 cannot be guaranteed. In some cases, noise was transmitted to DTE5 until DSU4 itself stabilized. As a result, the state mismatch between the DDX network 3 and the DSU 4 occurs,
Although the line does not turn off, the link between DDX network 3 and DTE5 is broken, but DTE5 cannot recognize the state of this link break because the link remains broken while the I line remains on. Was.

In addition, a noise interface generated between the DSU 4 and the RPC 5a may cause a malfunction of the line interface of the RPC 5a, thereby making it impossible to receive a message.

This is especially true of unmanned, 24/7 RPC5
The system a has the drawback that the system may be down, and it takes a long time to recover after a failure occurs.

Further, when such a state occurs, it is necessary for the operator to turn off and on the power of the entire DTE 5 by an operator. For this reason, when a file is transferred from a higher-level device unattended at night, the system cannot be recovered until an operator comes, and a serious system trouble such as the inability to operate the system for the first time in the morning has occurred.

Also, in order to solve such a point, the host device side
There is a method of constantly exchanging messages between DTE1 and DTE5 (parent device 5b) on the terminal device side at fixed intervals, but this becomes a load on the upper device and the parent device 5b and is charged for sending and receiving packets. There was a disadvantage that it would.

Therefore, an object of the present invention is to eliminate the above-mentioned conventional disadvantages, to prevent the occurrence of noise between the DSU and the DTE on the terminal device side and to prevent deadlock on the DTE side due to a failure in the communication network, and to operate unattended 24 hours a day. It is an object of the present invention to provide a highly reliable terminal device control device that can sufficiently withstand the above.

(Means for Solving the Problems) According to the present invention, in a control device of a terminal device connected to a higher-level device via a communication network, detecting means for connecting to an indication line of a line interface and detecting a signal change thereof, Sending means for sending a command for setting a link to the communication network; checking means for checking a response to the command; and initialization means for initializing the control device if the checking means cannot check the response. When a signal change of the indication line occurs, by confirming a response to the transmission of the command, the link is re-established, the signal change of the indication line does not occur, and When a response is not confirmed, the control device is initialized, the command is retransmitted, and the By confirming the response, the link is reset.

(Operation) Therefore, a command for causing the communication network to perform link setting is sent by the sending means, and if a response to the command is not confirmed by the checking means, the control device is initialized to initialize the communication network with the fault state of the communication network. A failure of the control device of the terminal device can be automatically recovered. Therefore, a highly reliable terminal device controller that prevents noise generation between the DSU and DTE on the terminal device side and deadlock on the DTE side due to a failure in the communication network and sufficiently withstands unattended operation 24 hours a day. Can be provided.

(Example) Next, an example of the present invention will be described with reference to the drawings.

FIG. 3 is a connection configuration diagram of the data communication system according to the present invention. The difference from FIG.
It has been replaced with DTE5 '. DTE 5 'is composed of RPC 5a' and parent device 5b. In FIG. 3, the same or corresponding parts as those in FIG. 2 are denoted by the same reference numerals.

FIG. 1 shows an embodiment of a terminal device control device (RPC) according to the present invention. In FIG. 1, an RPC 5a 'corresponds to a line interface section of a DTE 5', and a microprocessor 11 and a reset circuit 12 are shown. And a communication serial-to-parallel converter 13 using LSI, a change point detection interrupt circuit 14, line receivers 15, 16, a line driver 17, a ROM 18, a RAM 19, and the like. Reference numeral 20 denotes a data bus, 21 denotes a reset command, 22 denotes a reset output, and 23 denotes an interrupt line for transmitting a signal change on the I line. Further, the ROM 18 and the RAM 19 are used as memories for storing programs and data required by the microprocessor 11.

Further, the microprocessor 11 is used as a transmitting means of the present invention for transmitting a predetermined telegram (SABM command or reception enable (RR) command) to a communication network, here the DDX network 3. In addition, the microprocessor 11 is used as confirmation means of the present invention for confirming a response to the predetermined message, which is returned from the exchange on the DTE 5 'side of the DDX network 3 through the DSU 4 in this case. Further, the confirmation means of the present invention, here the microprocessor 11, detects the failure state of the communication network, here the DDX network 3 and the failure of the RPC 5a ', because the response to the prescribed message cannot be confirmed within a prescribed time. At this time, the microprocessor 11 and the reset circuit 12 are used as initialization means of the present invention for initializing the RPC 5a 'itself and the communication network (initializing the communication network).

The operation based on such a configuration will be described below.

Normally, from the host device side, via DSU2, DDX network 3, DSU4,
The received data input from the R line to the RPC 5a 'is converted from serial data to parallel data by the serial-to-parallel converter 13 and input to the microprocessor 11, where reception is determined.

On the other hand, transmission data from the terminal device side, that is, transmission data from the microprocessor 11 of the RPC 5a ', is converted from parallel data to serial data by the serial / parallel conversion unit 13, and transmitted to the T line. Then, the transmission data is transmitted to DTE1 on the host device side via DSU4, DDX network 3, and DSU2.

When the signal of the I line changes, the change point detection interrupt circuit
14 detects the change of the signal and notifies it to the microprocessor 11 through the interrupt line 23 in the form of an interrupt. Thereby, the microprocessor 11 can always recognize the state of the I line. Here, when the I line is turned off and restored to the on state, the microprocessor 11 operates as a change point detection interrupt circuit.
Assuming that the link has been disconnected by the notification from 14, the SABM command is converted to a serial / parallel converter to reset the link.
13, Transmitted to DSU4 via T line. The DSU 4 further transmits the SABM command to the exchange on the DTE 5 'side of the DDX network 3, and transmits a UA response from the exchange to the microprocessor 11 via the R line of the RPC 5a' and the serial / parallel exchange unit 13 of the RPC 5a '. . By receiving the UA response, the microprocessor 11 confirms that the link with the DDX network 3 has been reset. When the I-line remains on, the microprocessor 11 checks a link with the DDX network 3 and sends a receivable (RR) command at regular time intervals to the serial / parallel converter 1.
3. Send to DSU4 via T line. The DSU 4 further transmits this RR command to the exchange on the DTE 5 'side of the DDX network 3, and sends the RR response from the exchange to the R-line, RPC 5a' serial-parallel exchange unit.
It transmits to the microprocessor 11 via 13. The microprocessor 11 sends an RR command and returns the returned RR.
You will see the response. Microprocessor
When 11 confirms the RR response, it means that the DDX network 3 has not failed.

Next, the operation according to the present invention will be described below with reference to the sequence of FIG.

First, a link with the DDX network 3 is set. This is because, as described above, the microprocessor 11 sends the SABM command to the DDX network 3 via the serial / parallel converter 13, the T line, and the DSU4.
It is sent to the exchange on the DTE 5 'side. DSU4 is
The UA response is transmitted to the microprocessor 11 via the R line and the serial / parallel converter 13 to the DTE 5 'side. The microprocessor 11 confirms by receiving the UA response,
The link with the DDX network 3 is established.

Next, the microprocessor 11 similarly transmits the RR command at regular time intervals to the DDX via the serial / parallel converter 13, the T line, and the DSU4.
It is transmitted to the exchange on the DTE 5 'side of the network 3. The DSU 4 transmits an RR response from the exchange to the microprocessor 11 via the R line and the serial / parallel exchange unit 13. Microprocessor
No. 11 confirms by receiving the RR response from the exchange on the DTE 5 'side of the DDX network 3 that it is found that no failure has occurred in the DDX network 3 on the DTE 5' side.

The microprocessor 11 thus operates at regular time intervals.
Although the RR command is sent and the RR response from the DDX network 3 is checked, if a failure occurs in the DDX network 3 on the DTE 5 'side, the RR response is not transmitted to the microprocessor 11. At this time, the microprocessor 11 returns to RR
The command is sent to the serial / parallel converter 13, T line, DSU4
To the exchange on the DTE 5 'side of the DDX network 3 via That is, the microprocessor 11 retries the transmission of the RR command. By retrying this RR command transmission,
When the RR response from the exchange on the DTE 5 'side of the DDX network 3 is not returned to the microprocessor 11, the microprocessor 11 determines that the link has been disconnected and sends out a SABM command to perform re-link setting. In this case, if a UA response to the SABM command is returned from the exchange on the DTE 5 'side of the DDX network 3 to the microprocessor 11, relinking has been set.

However, the UA response to the SABM command is not
From the switch on the DTE 5 'side of the DDX network 3, the microprocessor 11
May not be returned (case shown in FIG. 4). This is because when noise occurs at the DSU4 interface, the noise pulse is out of the specified range.
This is because the serial-to-parallel converter 13 of the DTE 5 'itself malfunctions (deadlocks) and cannot receive the UA response. When the microprocessor 11 cannot receive the UA response to the SABM command, the microprocessor 11 issues a reset instruction to the reset circuit 12.
Send out 21. The reset circuit 12 sends a reset output based on the reset command 21 to reset the serial / parallel conversion unit 13, the change point detection interrupt circuit 14 and other peripheral circuits in the RPC 5a '. As a result, the microprocessor 11 restarts its operation from the initialization of the serial-parallel converter 13 and the like, and resets the serial-parallel converter 13 for initialization. And again DDX
A SABM command is sent to establish a link with the network 3. Note that even if the serial-to-parallel converter 13 malfunctions due to a noise pulse from the DSU 4, the reset is restored and the deadlock state of the serial-to-parallel converter 13 is released. Therefore, a UA response to the transmission of the SABM command can be received, and the data link between the DDX network 3 and the DTE 5 'has been set. In other words, the communication network,
In this case, initialization for performing data transmission between the DDX network 3 and the DTE 5 'has been performed. In this way,
The system can be completely restored.

As can be understood from the above description, in the present invention, the microprocessor 11 detects a failure of the communication network, here, the DDX network 3 irrespective of the state of the I line, by detecting whether or not the RR response to the RR command transmission is received. be able to. Further, the microprocessor 11 detects the failure of the DDX network 3 by receiving a UA response to the SABM command transmission or after resetting the serial / parallel conversion unit 13 or the like by the reset circuit 12 regardless of the state of the I line. The conversion unit 13 is reset, and after that, it can be recovered by receiving a UA response to the SABM command transmission. For this reason, DS
Even when the power supply of U4 is turned on / off or the instantaneous interruption of the AC100V line of DSU4 occurs, the system on the DTE 5 'side does not deadlock and a highly reliable RPC 5a' can be provided.

Also, in the event of a failure of the DDX network 3 and further of a failure of the serial-to-parallel converter 13 in the RPC 5a ', the recovery process by the operator is not required. Can be driven unattended.

Further, as described above, since the instantaneous interruption of the AC power supply of the DSU 4 is allowed, it is not necessary to use an expensive non-stop power supply (CVCF), and an economical system can be constructed.

The present invention is not limited to the present embodiment, and various applications and modifications can be considered without departing from the spirit of the present invention.

(Effects of the Invention) As described above, the present invention has the following various effects.

(1) Since a failure in the communication network can be detected and restored regardless of the state of the I-line, the communication network is activated by turning on / off the DSU on the terminal device side or generating an instantaneous interruption of the AC input of the DSU. Even if the connection status is poor (failure in the communication network) or noise occurs with the DSU, the system of the control device of the terminal device does not deadlock and the control of the terminal device with high reliability An apparatus can be provided.

(2) Even if a failure occurs in the communication network, and further, when a failure occurs in the control device of the terminal device, the recovery process by the operator is not required. Can be operated unattended.

(3) Since the instantaneous interruption of the AC power supply of the DSU on the terminal device side is allowed, it is not necessary to use an expensive non-stop power supply (CVCF), and an economical system can be constructed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a terminal device control device according to the present invention, FIG. 2 is a connection configuration diagram of a general data communication system, and FIG. 3 is a connection configuration diagram of a data communication system according to the present invention. FIG. 4 is an explanatory diagram showing an example of a sequence between the DTE and the DSU, and FIG. 5 is a diagram showing an interconnection circuit of a line interface between the DTE and the DSU in FIG. 3 DDX network, 4 DSU, 5 'DTE, 5a' RPC, 11 Microprocessor, 12 Reset circuit, 13 Serial-to-parallel converter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12 / 02,12 / 10,12 / 12 H04L 29/00-29/14

Claims (1)

(57) [Claims] 1. A control device for a terminal device connected to a higher-level device via a communication network, comprising: detecting means for connecting to an indication line of a line interface to detect a signal change thereof; and setting a link to the communication network. Transmitting means for transmitting a command to be transmitted, confirmation means for confirming a response to the command, and initialization means for initializing the control device if the response cannot be confirmed by the confirmation means, the signal of the indication line being provided. When a change occurs,
By confirming the response to the transmission of the command, the link is re-established.When the signal change of the indication line does not occur, and when the response to the transmission of the command is not confirmed, the control device is initialized. A terminal device control device for re-establishing a link by retransmitting a command and confirming a response to the transmission of the command.