JPS5941623B2 - Line monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line monitoring system, and more particularly, the present invention is provided with a plurality of line handling units and a common control unit, and the common control unit performs communication between the line and a central processing unit in response to a character processing request from the line handling unit. This invention relates to a line monitoring method in a communication control device that controls data transfer.

In a communication control device, for example, a signal line from a modem (
A data set ready signal DR line indicates that data is prepared, a gear IJ detect signal CD line indicates that a carrier has been detected, and a clear to cent signal CS indicates that a carrier is being sent. polarity of lines, etc.)
When monitoring, the common method is to use a timer to monitor at regular intervals, or to detect the conversion point of the signal line in the line handling section and notify the common control section.

When monitoring signal lines using a timer in a communication control device that does not have the above-mentioned conversion point detection function, the timer is generally used to monitor the time (on the order of seconds to minutes) for responses and messages from the other station. In order to reuse the existing timer used, the minimum unit of the timer is 1/10 second ~
It is on the order of seconds. Therefore, in high-speed lines, there have been cases where the signal line monitoring interval is too long, resulting in a decrease in line efficiency. Furthermore, the method of creating a new dedicated timer requires more hardware and is not economical. An object of the present invention is to use pseudo processing requests instead of timers to shorten the signal line monitoring interval according to the line speed.
Improve line efficiency by shortening the time required for switching from reception to transmission or from transmission to reception, etc. in two-wire half-duplex mode, and also provide means for early detection of faults in the modem, line termination equipment, or line. It is about providing.

In order to achieve the above object, the present invention includes a plurality of line handling units and a common control unit, and the common control unit transfers data between the line and the central processing unit in response to a character processing request from the line handling unit. In the communication control device to be controlled, a means is provided to generate a pseudo character processing request in the line corresponding section in addition to the character processing request, and the above two types of processing requests can be used alone or in combination according to the specification of the common control section, and the above The present invention is characterized in that the signal line from the modulation/demodulation device is monitored at the time any processing request occurs. Hereinafter, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of a communication control device, in which 1 is a common control section, 2 is a line handling section, 3 is a microprogram, 4 is a circuit that detects a processing request from the line handling section, and 5 is a processing It is a request signal. Common control unit 1
has an interface with the central processing unit, and the line corresponding section 2 has an interface with a modem and the like.

FIG. 2 is a diagram showing an example of the timing at which a processing request is issued from the line handling unit 2 to the common control unit 1, which is characteristic of the present invention, in which solid line arrows indicate character processing requests, and dashed line arrows indicate pseudo Indicates a processing request. Figure 2a shows an example of request generation timing when pseudo processing requests are used alone, and Figure 2b
This is an example of request generation timing when a pseudo processing request and a character processing request are used together, and the character processing request that is generated for each character length is stopped midway. The interval at which pseudo processing requests occur should be one character long or longer than the line speed of the target line (here, as an example, it is two characters long), and when pseudo processing requests are used alone, processing requests are made at the above intervals. occurs. When a pseudo processing request and a character processing request are used together, the pseudo processing request is generated after the above-mentioned two character interval from the time when the character processing request is generated. However, normally character processing requests are generated for each character length, so pseudo processing requests are not generated, and pseudo processing requests are generated at the above-mentioned intervals from the time when character processing requests stop occurring due to the clock sampling data on the line stopping. Operates to generate processing requests. next,
FIG. 3 is a block diagram of the line correspondence section 2 of the embodiment according to the present invention. In the figure, 10 is a character assembly/disassembly section, which includes an assembly buffer (AB) and a character buffer (CB).
11 is a character processing request generation circuit and a bit counter (BPC) in the character assembly/disassembly section 10;
It detects that one character has been assembled in the reception assembly buffer (AB) or that one character has been transmitted from the transmission assembly buffer (AB) based on the value of , and issues a character processing request to the common control unit 1. 12 is a counter which issues a pseudo processing request to the common control unit 1 every time it overflows and is reset each time a character processing request is generated in the character processing request generation circuit 11;
3 is a status register, which indicates that a received character is stored in the receiving character buffer (CB) or that a transmitted character in the transmitting character buffer (CB) is transferred to the transmitting assembly Ij buffer (AB). 14, which retains information indicating the status, etc., and also retains the polarity of the signal line (DR, CD, CS line, etc.) from the modulation/demodulation device.
15 is an AND circuit, 16 is an OR circuit, 17 is a transmitting/receiving data line between the modulator and demodulator, 18 is various signal lines from the modulator/demodulator, 19 is a transmitting/receiving data line between the common control unit 1, and 20 is a common This is a processing request signal line to the control unit 1, and corresponds to an interrupt signal to the common control unit 1. The signal on this signal line causes the common control unit 1 to perform processing to find the cause of the interrupt, resulting in line response. 21 is a character processing request enable line from the common control section 1, 22 is a pseudo processing request enable line from the common control section 1, 23 is a status information transmission line to the common control unit 1.

The operation of FIG. 3 is as follows.

First, as shown in FIG. 2a, when the pseudo processing request is used alone, the common control section 1 turns on the pseudo processing request enable line 22 and makes the AND circuit 15 conductive.
The counter 12 is always counting, and after counting up to the maximum value, it starts counting again from 0.

The time required to count up to this maximum value is, for example, selected to be twice the length of one character. Then, when the count reaches the maximum value and an overflow occurs, a pseudo processing request is issued and notified to the microprogram 3 of the common control unit 1 via the AND circuit 15, the OR circuit 16, and the processing request signal line 20.

Thereby, the Mitaro program 3 reads the contents of the status register 13 through the status information sending line 23, and identifies the polarities of the various signal lines from the modulator/demodulator. Next, as shown in FIG. 2b, when a pseudo processing request and a character processing request are used together, the common control unit 1 turns on both the character processing request enable line and the pseudo processing request enable line, and the AND circuit 14 and 15 are both brought into conduction.

While characters are being transmitted and received normally, since the interval between character processing request signals sent from the character processing request generation circuit 11 is shorter than the count period of the counter 12, the counter 1
2 is reset midway through without counting up to the maximum value. Therefore, normally only a character processing request is notified to the microprogram 3 of the common control section 1 via the AND circuit 14, the OR circuit 16, and the processing request signal line 20. The microprogram 3 reads the contents of the status register 13 via the status information sending line 23, and when it identifies that it is a character processing request, sends and receives the necessary data to and from the character assembly/disassembly unit 10 via the sending/receiving data line 19. . On the other hand, if the transmission and reception of data between the character assembling/disassembling section 10 and the demodulator is stopped for some reason, no character processing request is generated and therefore the counter 12 is not set to 1J. Therefore, after the last character processing request is generated, for example, pseudo processing requests are generated at intervals of two characters, and as described above, the microprogram 3 identifies the polarities of the various signal lines from the modulator and demodulator, and Processing is performed. An example of the use of the present invention is to use a pseudo processing request alone to monitor a signal line of a modem device or the like in the case of a high-speed line at intervals shorter than a timer in accordance with the line speed.

As a result, in controlling a slave station in two-wire half-duplex communication or calling, when switching from reception to transmission, after instructing the modem to turn RS on (0N), CS turns on (0N).
) can be detected at an early stage, and the efficiency of line usage can be increased. In addition, in cases where a character processing request is not generated until the line support section receives a specific synchronization character as shown in Figure 4, a pseudo processing request is also used, and when the microprogram determines that it is a pseudo processing request, By determining the state of the signal line of the modem, it is possible to detect failures in the modem and the line at an early stage.

In addition, by using a pseudo processing request and a character processing request together during the transmission or reception of a message, and recognizing the occurrence of a pseudo processing request, the data sampling clock supplied from the modem, etc. to the line corresponding section on the synchronous line can be It is possible to detect the stoppage of the As described above, according to the present invention, a means for generating a pseudo character processing request in addition to a character processing request is provided in the line handling section, and the signal line monitoring interval is shortened, so that the line usage rate is reduced. This has the excellent effect of not only increasing the performance of the network, but also detecting line failures at an early stage.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the communication control device, Fig. 2 is a diagram showing an example of processing request generation timing, Fig. 3 is a block diagram of the line corresponding section of the embodiment according to the present invention, and Fig. 4 is a character processing request. FIG. 4 is a diagram illustrating an example of using a pseudo processing request and a pseudo processing request together.

Claims (1)

[Claims] 1. In a communication control device that is equipped with a plurality of line handling units and a common control unit, and in which the common control unit controls data transfer between the line and a central processing unit in response to a character processing request from the line handling unit, A means is provided to generate a pseudo character processing request in addition to the processing request, and the above two types of processing requests can be used alone or in combination according to the specifications of the common control unit, and the modem can be activated at the time when either of the above processing requests is generated. A line monitoring method characterized by monitoring signal lines from.