JPS62245834A - Multi-address communication system - Google Patents

Abstract

PURPOSE:To confirm the reception of a multi-address frame without causing collision of reply frames by providing a timer section deciding the transmission timing of a reply signal at different standby times to each data transmission/ reception equipment. CONSTITUTION:Suppose that the data source and sink 1a outputs a multiple address frame to a communication line 2. A multi-address frame detection circuit 114 outputs a detection signal 114a near at the same time in data source and sinks 1b, 1c, 1d receiving a multi-address frame Ga. Each timer section 115 of the data source and sinks 1b, 1c, 1d is set with standby times Tb, Tc, Td and reply signals Rc, Rb, Rd are outputted in this order from the data source and sinks 1c, 1b, 1d. The data source and sink la receives the signals and the reception of the multi-address frame Ga by all the data data source and sink is confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a broadcast communication system that can simultaneously transmit predetermined signals to data transmitting and receiving devices connected to a communication line.

[Conventional technology]

In a system where multiple data transmitting/receiving devices are connected to a communication line and transmitting/receiving various types of information, the multiple data transmitting/receiving devices simultaneously receive and process the information sent from one of the data transmitting/receiving devices. There is something.

Such a system is called a broadcast communication system.

In this broadcast communication system, first, one data transmitting/receiving device sends out a broadcast frame having a predetermined bit configuration onto a communication line. This broadcast frame includes a code, information, etc. that identifies the data transmitting/receiving device that sent it.

This broadcast frame transmitted to the communication line is received by a plurality of data transmitting/receiving devices connected to the communication line almost simultaneously, if the signal propagation time is ignored.

When each data transmitting/receiving device receives this broadcast frame, it is preferable that the data transmitting/receiving device that sent it confirms it.

One conceivable way to do this is to use a method in which each data transmitting/receiving device outputs a specific response frame to the communication line when receiving a broadcast frame.

However, if each data transmitting/receiving device receives broadcast frames almost simultaneously and outputs response frames at the same timing, these devices will collide on the communication line.

Such a collision of response frames may cause interference, frame loss, deadlock, etc.

Note that frame loss is a phenomenon that occurs when frames with contents of opposite polarity are superimposed, and deadlock is a phenomenon in which processing cannot proceed further due to frame collision.

[Problem that the invention seeks to solve]

For these reasons, conventional broadcast communication systems have generally adopted a system in which no response frame is sent, that is, the reception of a broadcast frame is not confirmed.

However, this poses a problem in that it is difficult to ensure that the broadcast frame has been received by all necessary data transmitting/receiving devices, making it difficult to further improve the reliability of the system.

The present invention has been made with attention to the above points, and an object of the present invention is to provide a broadcast communication system in which reception of a broadcast frame can be confirmed for each data transmitting/receiving device without causing a collision of response frames. The purpose is to

[Means for solving problems]

The broadcast communication system of the present invention includes a communication line and a plurality of data transmitting/receiving devices connected to the communication line, and the data transmitting/receiving device includes one of the above data transmitting/receiving devices connected to the communication line. a receiving unit that receives the broadcast frame transmitted by the broadcast frame, a response unit that transmits a response signal to the communication line when the reception unit receives the broadcast frame, and a timing at which the response signal is sent by the response unit. The timer unit determines the response signal so that the waiting time from receiving the broadcast frame to transmitting the response signal is a different value for each data transmitting/receiving device. This feature is characterized in that the timing of transmitting the data is determined.

[Effect]

As described above, in the broadcast communication system of the present invention, each data transmitting/receiving device is provided with a timer section that determines the timing of transmitting a response signal using mutually different waiting times.

By doing so, the response signals of all the data transmitting/receiving devices are sequentially transmitted to the communication line without collision, and the reception of the broadcast frame can be confirmed for all the necessary data transmitting/receiving devices.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a data transmitting/receiving device 1 used in the broadcast communication system of the present invention.
It is assumed that a plurality of such data transmitting/receiving devices 1 are connected to.

Here, this data transmitting/receiving device 1 includes a data transmitting/receiving device 11 that receives and receives signals on a communication line 2 or sends signals to the communication line 2, and a data processing device 10 that processes data to be transmitted and received. It is composed of.

The data processing device 10 is comprised of, for example, a facsimile machine, a personal convenience store having a communication function, or the like.

The data transmission device 11 includes a receiving section 111 that receives a signal from the communication line 2, a first-in first-out memory 112 (FIFO) that buffers the signal for a certain period of time, and a transmitting section 113 that sends the signal back to the communication line 2. It is equipped with This part is no different from known devices.

Further, if the signal received by the receiving section 111 includes a broadcast frame, the broadcast frame tJ to detect this
[] path 114 and a timer circuit 1 that measures a certain waiting time from the manual operation of the detection signal 114a outputted by this circular frame detection circuit 114 and outputs a response command 115a.
15, and a response unit 1 that outputs a predetermined response frame 116a toward the transmission unit 113 according to the response command 115a.
16 are provided.

Further, the signal received by the receiving unit 111 is stored in a buffer memory 117 and read and processed by the data processing device 10, and a predetermined signal output from the data processing device 10 is stored in the buffer memory 118. The configuration is such that the signal is transmitted to the communication line through the transmitter 113 at a predetermined timing.

The transmitting section 113 is composed of a circuit that combines known amplifiers and the like that suitably synthesizes human input signals from the first-in first-out memory 112, the response section 116, and the buffer memory 118, and outputs the synthesized signals to the communication line 2. .

The broadcast frame detection circuit 114 is composed of a comparison circuit and the like, and when the human signal is a broadcast frame, the detection signal 114a
This is a circuit that outputs .

The timer section 115 is composed of a counter circuit or the like in which a count value corresponding to a standby time uniquely selected for the data transmitting/receiving device 1 is set in advance. This timer section 115 clears the counter by cello-clearing the detection signal 114a output from the broadcast frame detection circuit 114.
This circuit counts and increments the clock pulses used to control the device, and outputs a carry when the set count value is reached. This carry is used as a response command 115a.

It is assumed that the response unit 116 has a circuit that outputs a response frame consisting of a self-identifying code, etc., and this circuit is activated by the response command 115a output from the timer unit 115.

The broadcast communication system of the present invention having the above configuration operates as follows. This operation will be explained with reference to FIG.

FIG. 2 shows an example of the broadcast communication system of the present invention, in which four data transmitting/receiving devices 1 are connected to a communication line 2. As shown in FIG. Each data transmitting/receiving device 1 has a first
The block configuration is as shown in the figure.

Here, it is assumed that the data transmitting/receiving device 1a outputs a broadcast frame toward the communication line 2. This broadcast frame propagates on the communication line 2 in the direction of the arrow, and is transmitted to each data transmitting/receiving device 1.
d and are received by the IC 11b almost simultaneously. At this time, each data transmitting/receiving device 1b.

The lc and ld operate so that the received broadcast frame is transferred to the adjacent data transmitting/receiving device via the first-in, first-out memory 112 shown in FIG.

Incidentally, the timing of the signal propagating to the communication line 2 is illustrated in the lower part of FIG. 2 along the time axis in the horizontal direction. Here, it is assumed that the data transmitting/receiving device 1a outputs the broadcast frame Ga at the timing indicated by the dot-dash arrow.

Each data transmitting/receiving device 1b that received this broadcast frame Ga
, lc, and 1d, detection signals 114a are output almost simultaneously from the broadcast frame detection circuit 114 shown in FIG. Each data transmitting/receiving device 1b, lc, l
The timer unit 115 of d has standby times Tb and Tb, respectively.
c and Td are set. The size relationship is as follows.

Tc<Tb<Td According to this, each data transmitting/receiving device IC1Ib.

Response signals Rc, Rb, and Rd are output in this order from 1d. The timing is also illustrated in FIG.

In this way, when the broadcast frame Ga is output, the data transmitting/receiving device IC outputs the response frame R after a time Tc from that time.
c, and after a time Tb, the data transmitting/receiving device 1b outputs a response frame Rb, and after a time Td, the data transmitting/receiving device 1d
outputs a response frame Rd. This response frame Rc
, Rb, and Rd are appropriately shifted from each other, the data transmitting/receiving device 1a can receive this and confirm that all the data transmitting/receiving devices have received the broadcast frame Ga. Note that the waiting time set in the timer section 115 of each data transmitting/receiving device is preferably selected so that each response frame is lined up with a slight interval from each other, as shown in the figure.

It goes without saying that the connection order of the data transmitting/receiving devices and the order of the length of standby time may be arbitrarily selected.

[Modified example]

The broadcast communication system of the present invention is not limited to the above embodiments.

The configuration of the data transmitting/receiving device does not necessarily have to be as in the embodiment. For example, the response section may output a response frame at the same time as the broadcast frame is received, and the timer section may delay the response frame for a predetermined period of time before transmitting it to the communication line. Furthermore, the receiving section, the timer section, and the responding section may be constructed from an integrated circuit instead of separate circuits.

Furthermore, although the communication lines are shown as being connected in a loop, they may also be in the form of a tree.

〔Effect of the invention〕

According to the broadcast communication system of the present invention described above, response frames are sent from each data transmitting/receiving device to the communication line at different timings, so there is no collision between them, and the reception of the broadcast frame can be confirmed. It can be carried out.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a data transmitting/receiving device used in the broadcast communication system of the present invention, and FIG. 2 is an explanatory diagram of an example of the system configuration and its operation. 1, la, lb, lc, ld...data transmitting/receiving device, 2...communication line, 111...receiving section,
115...Timer section, 116...Response section. Applicant: NEC Corporation Representative

Claims (1)

[Claims] It has a communication line and a plurality of data transmitting/receiving devices connected to the communication line, and the data transmitting/receiving device receives a broadcast frame sent by any of the data transmitting/receiving devices to the communication line. a receiving section that transmits a response signal to the communication line when the receiving section receives the broadcast frame, a response section that transmits a response signal to the communication line when the reception section receives the broadcast frame, and a timer section that determines the timing at which the response signal of the response section is sent. and the timer section determines the sending timing of the response signal so that the waiting time from the reception of the broadcast frame to the sending of the response signal is a different value for each data transmitting/receiving device. Features a broadcast communication system.