JP2750934B2 - Communication method in multi-connection - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a communication system for connecting a main device and a sub device on the same line.

[Conventional technology]

2. Description of the Related Art Conventionally, when a main device and a plurality of sub devices are multi-connected on the same line, communication is performed between the main device and the sub devices by inquiring of the presence or absence of transmission data.

[Problems to be solved by the invention]

In the above prior art, the sub device cannot transmit data without an inquiry from the main device.

In addition, the main equipment must perform the inquiry process at regular intervals regardless of the presence or absence of data on the sub device side.

Furthermore, when data is transmitted to the main device by pressing the push button on the sub device side and the response of the sub device is controlled by the response, if the number of inquiries to the sub device on the main device side is small, the lamp is displayed. The response that changes is slow. However, if the number of inquiries is increased, the processing load on the main apparatus becomes heavy, and the processing originally owned by the main apparatus cannot be performed. Therefore, a dedicated processor must be separately provided to distribute the processing.

An object of the present invention is to reduce the processing load on the sub device on the main device side and to liberalize data transmission on the sub device side.

[Means for solving the problem]

The above purpose is to make the connection form between the main device and the sub device all the same, and if one device sends some data to the line, all connected devices recognize that there is data on the line. Make a connection that can be made, check that each device has no data on the line, set the method to transmit the desired data, and use the received data that is unrelated to the device or data that caused an error If no response is received for the transmitted data, and if there is no response to the transmitted data, a line contention with another device has occurred, or the transmitted data has an error due to noise or the like. This is achieved by retransmitting the data after a random time multiplied by an integral number of times from the transmission of the data to the return of the reply from the transmission of the data.

[Action]

According to the present invention, in the main device and the sub device that are multi-connected on the same line, the sub device does not depend on the control of the main device,
Since data can be transmitted over the line and the main device does not need to inquire the sub-device of the presence or absence of transmission data, the processing load on the sub-device on the main device side is reduced and the sub-device side Data transmission can be liberalized.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a system configuration of a hotel room indicator according to an embodiment of the present invention. MINSYS1−
Reference numeral 1 denotes a telephone charge management device which is a main device.
-2 indicates a room indicator (a lamp panel with a push button) which is a sub device.

FIG. 2 shows the internal configuration of SUBSYS, and data necessary for operation is stored in DTMEM2-6 by a push button of SUBSYS itself.

Hereinafter, a data transmission / reception sequence using the present invention will be described in detail.

In FIG. 2, when the SUBSYS push button is pressed, the information is stored in KYMEM2-1, the lamp information corresponding to the pushbutton at that time is referred to by the LEDMEM2-2, and the transmission data is stored in the TMEM2-
Create in 3. Next, the created data is transmitted.

In FIG. 3, first, the presence or absence of data on the line is checked (3-1). If there is no data on the line, DISTIM
It is determined whether the transmission prohibition timer is set in 2-4 (3-2). If not set, the data in TMEM2-3 is sequentially transmitted to SYSINF2-9 via CPU2-8 (3-3). After that, it has reply data for a certain time (3
-4). If the response data is not returned, it is determined that contention for the line with another device has occurred, and the time from the transmission of the data to the return of the response data is obtained from the data length,
A timer obtained by multiplying the above-mentioned time by an integer based on the random number by RANDOM2-7 is used as a random transmission prohibition timer as DISTIM.
Set to 2-4 (3-5).

Next, the response data receiving process will be described. 4th
In the figure, first, the presence or absence of data on the line is checked (4-1). If there is data, receive buffer RMEM2-5
(4-2). The presence or absence of an error in the received data is checked (4-3). If there is no error, the data in the reception buffer is compared with the data stored in advance in the DTMEM2-6 to determine whether the data is relevant (4-4).
If the data is relevant, the LED lighting data stored in the LED MEM2-2 is changed (4-5), and a reply is transmitted (4-6). If the data is irrelevant, it recognizes that the other device returns a response, and sets the transmission prohibition timer for that time in DISTIM2-4 (4-7). In addition, (4-
If there is an error in the received data in the item 3), it is determined that contention has occurred with another device, and the random transmission prohibition timer is set in DISTIM2-4.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, in the mutual communication of the main apparatus and the sub apparatus which are multi-connected on the same line, the main apparatus does not have to perform the inquiry about the presence / absence of data to the sub apparatus at regular intervals. Therefore, the process during that period can be assigned to another process.

In addition, the sub device can immediately transmit data by independent judgment without depending on the control of the main device.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a hotel room indicator according to an embodiment of the present invention, FIG. 2 is an internal configuration diagram of a room indicator (SUBSYS) of FIG. 1, FIG. 3 and FIG.
The figure shows a flowchart of data transmission and reception using the present invention. 1-1: Main device (call information processing device) 1-2: Sub-device (hotel room indicator) 1-3: Distributor 2-4: Transmission prohibition timer storage memory 2-7: Random number generator 2-8: Central processing unit 2-9: Multi connection interface

Claims (1)

(57) [Claims] 1. A main device and a sub device are connected to the same communication line, and the sub device monitors an idle state of the communication line. If the communication line is idle, a predetermined transmission is immediately performed. In a multi-connection communication system for transmitting data and mutually transmitting a message between the main device and the sub device, the sub device transmits the transmission data to the main device, Determining means for determining whether a response signal has been received from the main device within the time; and determining that the response signal has not been received within a predetermined time based on a data length of the transmission data. Calculating means for calculating a response time from transmission of the transmission data to reception of the response signal; obtaining a value obtained by multiplying the response time by a random number by an integer; and setting the value as a transmission prohibition time Means Means for retransmitting the transmission data to the main device after the transmission prohibition time has elapsed.