JPS5990442A - Communication control equipment - Google Patents

Abstract

PURPOSE:To decrease the detecting time of non-communicating state by providing one timer, setting the 1st time to the timer just after the transmission of a call signal, and setting the 2nd time if the data is during receiving after the elapse of the 1st time to monitor the receiving state. CONSTITUTION:A processing section 6 transmits a calling signal P and sets a time T1 to the timer C. The time T1 is at least a time by which the head block of the response data is received. When data D is received from the terminal, a length (m) of a local memory 4 is set to a counter 12 every time one byte of data is received, after ''1'' is added, the length (m+1) is stored in a memory 4. When the data of a memory section M1 is at ''0'' at the time t1, it means no receiving, the processing section 6 calls another terminal device, sets the time T1 again to the timer C and continues the monitor of line again. When the read data is not ''0'', the processing section 6 sets a time t2. The time T2 is taken as a time longer the time required for the receiving of data having the maximum block length. Thus, the end of reception is detected by checking the data in the memory section M1 from the processing section 6 after the elapse of the time T2.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a communication control device that controls data transmission and reception in a polling system.

(b) Prior art and problems In a system in which a plurality of terminal devices are connected to the main processing unit m of a center via a communication control device E7, after the communication control device issues a polling signal to the terminal side, The communication control device monitors the presence or absence of data sent from the terminal side. As a means for monitoring this time, a timer is set to a time that exceeds the time required to receive the largest block of data (defined by the system), and this timer is activated after the polling signal is issued. If no data is received after a set time has elapsed, a method is adopted in which it is assumed that there is no response. This conventional method has the disadvantage that it takes time to detect a non-communication state because the timer is set at a certain time. In order to improve this, a method has been adopted in which a second timer for detecting a non-communication state is provided and the non-communication state is detected by detecting the number of consecutive bits of received data. However, although this method allows early detection of the presence or absence of received data, timer 7?
211^1 is required, which has the disadvantage of requiring a large circuit configuration.

(c) Purpose of the invention The present invention has been made to solve the above-mentioned drawbacks.
An object of the present invention is to provide a communication control device that facilitates detection of the presence or absence of received data.

(d) Structure of the Invention The present invention is characterized in that a processing device and a communication control device of a center, and a terminal device are connected to each other via a communication line, and a predetermined maximum block is generated by the terminal device in response to a call signal from the communication control device. A system in which a communication control device receives data having a predetermined length, comprising: a timer; a first time setting means for setting a relatively short first time fixed in the system to the timer; a second time setting means for determining a 20th time that is long and exceeds the time required to receive data of the maximum block length; a means for activating the timer; and a determining means for detecting the presence or absence of the received data. and after transmitting the paging signal, sets the first time in the timer, and when the timer is receiving data from the terminal device after the first time elapses, the timer is set to the first time. The communication control device is characterized in that when the time of 2 is set or data is not being received, it is assumed that there is no response and the call signal is transmitted to another terminal device. As described above, the present invention provides one timer for time monitoring, sets a first time in this timer immediately after sending a polling (calling) signal, and determines whether there is received data after this time elapses. However, if data is being received, a time of m2 (time that exceeds the time required to receive the maximum block length) is set in the timer, and the reception status is monitored. The first time set in the timer is set in consideration of the delay time of the modem and the communication line, and is extremely short compared to the second time. If data reception is completed within the first time period, the timer may be stragged at that point and a polling signal may be sent to another terminal device. By doing so, it becomes possible to shorten the detection time of a non-communication state.

(e) Examples of A-Ming The present invention will be explained below with reference to the drawings. FIG. 1 is a block diagram illustrating one embodiment of the present invention.

Terminal devices A-Z in FIG. 1 are modems (not shown),
It is connected to a communication control device 2 by a communication line 1. It has a communication control device, two sub-processing devices 3, a local memory 4, a control section 5, and a timer C.

The communication control device 2 issues a polling signal P to the terminal devices A to Z, and the terminal devices t (A to Z) that responded to the polling signal P send data D, but the communication control device 2 It is necessary to monitor the time. For this reason, a timer for time monitoring is required, but in the present invention, one timer C can detect received/first-pass data and detect the end of data reception. In FIG. 1, the processing section 6 issues a polling signal P after clearing the memory section M of the local memory 4, and sets a timer C to 41 hours T. This time T is set in consideration of communication delay as described above, and is the time during which at least the first block (frame) of polling response data on the terminal side can be received. Note that in the embodiment, a time is set during which several frames of response data can be received. When data D is received from a terminal device (for example) A that responded to the polling signal P, each time a byte is received, the hardware sets the length m of the local memory 4 in the up/down counter 12, increments it by 1, and then returns the data to the multiplexer 10. The length m+1 is stored in the local memory 4 through . When the processing section 6-digit timer C reaches a predetermined time, the memory section M1 of the local memory 4 is accessed and read. If the read data is “0” (length is zero),
Since the data is not yet received, the processing unit 6 sends the baud +1 to another terminal device and then sets the timer C again for the time T.
Set. As a result, line monitoring (whether or not received data has arrived) is continued again. In contrast, memo 11e1M in memory 4,
”, it indicates that data is being received, so the processing unit 6 sets timer C to time T2.

This time T2 is the time that exceeds the time required to receive data of the maximum block length. Therefore, the counter C is the time T,
After the processing section 6 has passed, the processing section 6 stores the memory section M of the local memory 4.
By checking the data (block length) within , it is possible to detect the end of data reception.

FIGS. 2 and 3 are time charts explaining the above operation. In FIG. 2, timer C is set to time T.

8- is set, and no data is received even after this time T has elapsed. In FIG. 2, the processing section 6 of FIG. 1 sends out a polling signal P1 to the transmission line S at time t, and after setting a time T1 to a timer C, starts the timer C. At time t4 after this time T1 has elapsed,
The processing unit 6 stores a memory unit M of the local memory 6.

As shown by the broken line in FIG. 2(d), there is no received data and there is a memo υM.

(length is zero), the processing unit 6 considers that there is no response and sends a polling signal P to another terminal device.

is sent to the transmission port, fdS, and after setting timer CK8 and time TI'r', it is activated. On the other hand, an example in which received data is detected is shown in FIG.

In FIG. 3, after transmitting the polling signal P at time t1, the processing unit 6 sets a time T1 to the timer C and starts the timer C. The data D from the terminal device in response to the polling signal P is transmitted at time t2 as shown in the third [Yl(c)].
When the reception starts, the ↓ shown in Figure 3 (d)
At time t, block length BL (
numerical data) is written. Timer C setting time T, 8
When the data in the memo 11 section M+ is checked at the elapsed time t4, it is found that the data is being received because BL→0.

As a result, the processing unit 6 performs the processing as shown in FIG. 3(b) (at time t).

), set timer C to 1d time T, and then start it. Since the set time T of timer C is longer than the time to receive data of the maximum block length,
After the set time T2 has elapsed, that is, at time t6, there should be no data being received, and if data is being received at this time, the processing unit 6 performs error processing. Set time T to timer C, and T.

If the relationship T, < T is selected, the detection time of the received data will be faster, and since the time TI is large enough to receive data of the maximum block length, it will be easier to detect the end of reception. (f) Effects of the Invention As described above, the present invention simplifies the circuit configuration because only one counter is required for time monitoring, and the time required to detect a non-communication state is shortened. This has the advantage that the polling cycle for terminal devices can be shortened and data collection efficiency can be improved.

4. Brief explanation of the drawings Figure 1 is a block diagram illustrating an embodiment of the present invention, Figure 2 is a block diagram illustrating an embodiment of the present invention.
3 and 3 are time charts for explaining one embodiment of the present invention, and the symbols used in the figures are as follows: 0 1 is a communication line, 2 is a communication control device, 3 is a sub-processing device, 4
is a local memory, 5 is a control unit, 6 is a processing unit, 7 is a transceiver, 8 is a bus, 9 is a driver 8-

Claims (1)

[Claims] The processing device and communication control device of the center and the terminal device are connected to each other via a communication line, and the terminal device responds to a call signal from the communication control device and transmits data with a specified maximum block length. A system that is received by the f1 control device includes a timer, a first time setting means for setting a relatively short first time fixed to the system in the timer, and a timer that is longer than the first time and has the maximum block length. second time setting means for setting a second time that exceeds the time required to receive the data; and means for activating the timer;
determination means for detecting the presence or absence of the received data, and after transmitting the ejection signal, sets the first time 8 in the timer, and the timer receives the data from the terminal device after the first time elapses. When receiving, the second time is set in the timer, or when receiving the data tree, it is assumed that there is no response and the calling signal is transmitted to another terminal device d. Communication control device.