JPS63149937A - Data communication control system - Google Patents

Abstract

PURPOSE:To attain data communication between data communication equipments even if the number of stations exceeds 254 by transmitting a random number between its own station and an opposite station to each other in a frame of global address, and adding a procedure deciding each station address depending on the largeness of the number. CONSTITUTION:When both stations A, B are in phase P1, that is, in the data link interrupting state, each station transmits a random number generated in advance by using global address frames 3, 4 and in receiving the frame of the global address of the opposite station, the random number of its own station and the opposite station is compared. In such a case, the larger random number is selected to be an address a1 and the smaller random number is selected to be an address a2, then the address of both the stations is decided. Thus, it is not required to feed a station address in advance to each data communication equipment, and every if the number of stations exceeds 254, the data link is established between optional data communication equipments to transmit/ receive the data.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to high-level data link control procedures (hereinafter referred to as
The present invention relates to a data communication control method for a device that performs data communication using HDLC (called HDLC) or a procedure based on HDLC.

[Prior Art] Figure 3 shows a conceptual diagram of a conventional data communication device.
(5) is a data communication device, which is composed of a data transmission section (6) using HDLC and a data processing section (7).

Further, (8) is a communication line.

In this configuration, when transmitting data, the data processing unit (7) processes the data to be transmitted, and the data transmission unit (6) that receives the data transmits the transmission data to the communication line (8) based on HDLC. In addition, communication lines (
The received data sent via 8) is taken into the data transmission unit (8) based on the HDLC, and the data transmission unit (6) passes this received data to the data processing unit (7) and processes the data. The processing unit (7) processes the received data.

FIG. 4 shows a conceptual sequence diagram showing a data communication control method between data communication devices having the above configuration, in which (1) is an operation mode setting command and (2) is a response to this command. Also, the phase (Pl
) indicates a data link disconnected state, and phase (P2) indicates a data link established state.

Next, the data communication control method here will be explained.

Here, it is assumed that the A station and the B station already have separate station addresses. Data link disconnected state (Pl
), when station A sends the operation mode setting command (1), station B sends a response (2) to this command (1), and when station A receives this response, the data link is established. Letter of establishment! (P2), and from now on, data can be transmitted and received between the A station and the B station.

Here, the format of a frame in HDLC is shown in FIG. 5. In HDLC, all data is transmitted and received in units of frames, but as shown in the figure, the address part consists of 8 bits. An address in which all 8 bits are 1 is called a global address, and this frame can be sent to a station at any address, and an address in which all 8 bits are 0 is called a no-station address.
Even if this frame is received, it is specified to be ignored.

Therefore, the station address that can be defined is 28-2 = 2
Up to 54.

[Problems to be solved by the invention] In the conventional data communication control system, when the number of stations exceeds 254, there are data communication devices with the same station address. There was a problem in that data could not be sent and received between communication devices.

This invention was made to solve the above-mentioned problems, and it eliminates the need to individually assign a station address to each data communication device in advance, and reduces the number of stations to 25.
An object of the present invention is to obtain a data communication control method that can establish a data link between arbitrary data communication devices even if the number of data communication devices exceeds 4, and can transmit and receive data.

[Means for Solving the Problems] The data communication control method according to the present invention transmits random numbers generated by each device to each other in a global address frame before establishing a data link between data communication devices. , the station address is determined by comparing the magnitudes of the numbers.

[Operation] In the present invention, since the station address is determined by the method described above, there is no need to assign a separate station address to each data communication device in advance.

[Embodiment] An embodiment of the present invention will be described below with reference to the sequence diagram shown in FIG. In Figure 1, (3) is a global address frame whose information is a random number generated by the data communication device of station A, and (4) is a global address frame whose information is a random number generated by the data communication device of station B. in,(
1), (2), (PL), and (P2) are the same as in the conventional example.

In the figure, when both stations A and B are in phase (Pl), that is, in a data link disconnected state, each station uses random numbers generated in advance to create global address frames ((3) and (4)). Send using . When a frame with the global address of the other station is received, the value of the random number of the own station and the value of the random number of the other station are compared. At this time, the larger value of the random number is the address al, and the smaller value is the address a.
If it is set to 2, the addresses of both stations will be determined. However, both al and a2 are 8 bits, a1≠a2, and are neither global addresses nor no-station addresses.

For example, the address of station A is determined to be al, and the address is a.
If station A is to send the operation mode setting command, as shown in the figure, station A will send the operation mode setting command (1
), station B receives this command and transmits a response (2), and station A receives this response and enters phase (P2), that is, a data link establishment state.

Here, FIG. 2 shows a conceptual diagram of the data communication device according to the present invention. (8) is a random number generation section, and (5) to (8) are similar to the conventional data communication device shown in FIG. be. The data processing unit (7) converts the random number value to the random number generation unit (8).
The data communication device according to the present invention operates in the same manner as the conventional one, except that processing for random numbers is added as described above.

Although the above embodiment describes a data communication device with more than 254 stations, for example, data communication devices with the same hardware and software configurations will both have the same station address. Data communication between such data communication devices can also be realized by using the data communication control method.

[Effects of the Invention] As described above, according to the present invention, a procedure is added in which random numbers are transmitted between the local station and the other station in a global address frame, and each station address is determined based on the magnitude of the number. Therefore, even if the number of stations exceeds 254, data communication can be performed between data communication devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic sequence diagram of a data communication control method according to an embodiment of the present invention, and FIGS. 2 and 3 are conceptual diagrams showing a data communication device according to an embodiment of the present invention and a conventional data communication device, respectively. 4 is a sequence schematic diagram showing a conventional data communication control method, and FIG. 5 is a diagram of an HDLC frame format. In the figures, (3) and (4) are frames of group addresses using random numbers as information. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3 Procedural amendment (voluntary)

Claims (1)

[Claims] In a data communication device that performs data communication based on the high-level data link control procedure standardized by the International Organization for Standardization or a procedure based on this, when starting data communication, a random number is sent between the local station and the other station in a global address frame. A data communication control method characterized by transmitting data to each other and determining each station's address based on the size of the numbers.