JPS6239864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a branch line communication system for a data exchange network having a branch line into which a plurality of lines branch.

When communicating via a branch line of a data exchange network, the switching equipment establishes a one-to-one communication state with each terminal device in the branch line by adding a terminal address, etc., and sends a sequence such as an acknowledgment response. There is a method of transmitting the same information to n terminal devices in a 1:n communication state with the terminal devices in the branch line, and before performing the latter broadcast communication. Conventionally, confirmation of the terminal status, confirmation of delivery after the end of communication, etc. cannot be carried out repeatedly from two terminals, so the former one-to-one communication is performed.

Therefore, until confirmation is obtained for all terminal devices,
Data transfer is performed by repeatedly turning the carrier on and off, which takes a long time to confirm, and the sequence is complicated.

In other words, in a system that performs broadcast communication to multiple terminals within a branch line, response information from terminals is
Since each terminal receives the response information, it takes a long time in total to receive response information from all the terminals, making the sequence complicated.

The present invention enables a switching device to send out a control signal requesting responses from multiple stations using the same signal, to receive and identify response signals from multiple terminal devices at the same time, and to enable the terminal devices to receive this control signal. , by making it possible to send out a response signal that can be identified as received, the above drawbacks are eliminated and the terminal response time is shortened,
The purpose is to provide a branch line communication system with a simplified sequence.

A feature of the present invention that achieves the above object is that when performing broadcast communication on a branch line, a control signal is provided to request an acknowledgment from each terminal at the same time, and a frequency unique to each end is assigned to the acknowledgment. The switching device can recognize the response even if it receives multiple frequencies at the same time by transmitting control information requesting an acknowledgment signal and having a device that distinguishes from which terminal the response signal was issued. On the other hand, the terminal device has a means for identifying the acknowledgment request signal, and is provided with a signal sending circuit that transmits an acknowledgment at a frequency unique to the terminal when the acknowledgment request signal is confirmed to the exchange device. .

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a switching device according to an embodiment of the present invention. In FIG. 1, 11 is a switching device 10.
This is a line compatible device that interfaces the digital data of the communication control device 15 with the modulated digital data on the line. Reference numeral 12 denotes a frequency discrimination device that receives a frequency signal coming from at least one terminal device, discriminates this frequency signal with a frequency filter, and delivers it to a frequency detector as a response signal for each terminal device. 13a,1
3b, 13c, 13a', 13b', and 13c' are frequency discrimination devices that detect the presence or absence of response signals from terminal device A, terminal device B, terminal device C, terminal device A', terminal device B', and terminal device C', respectively. 12, and communicates to the control information transmitter 14. 14 transmits a control signal requesting a confirmation response to each terminal device through the communication control device 15 when a transmission request to a terminal device is generated via the central processing unit 16, and monitors confirmation information from each terminal device. This is a control information transmitting unit.

FIG. 2 is a block diagram of a terminal device according to an embodiment of the present invention. In FIG. 2, information from the line is transferred to the communication control device 24 through the line support device 21 of the terminal device, transmission control is performed in this communication control device 24, and this information is transferred from the switching device 10. When identifying that it is control information for an acknowledgment request,
The information is transmitted to the response information transmitting section 22. The response information transmitting section 22 controls the signal transmitting section 23a to send a signal when the data reception preparation is completed. The signal sending unit 23a is the frequency detector 1 of the exchange device 10.
3a, and transmits this frequency signal as a response signal to the switching device 10 via a line.

An example of the operation sequence of the branch line communication system having the above configuration will be explained with reference to FIG. The exchange device 10 sends the same information to terminal devices A and B after RSON.
A frame called FRAME·S(A,B) is used to inform the terminal device that transmission is to be started. Terminal devices A and B receive this frame and become ready to receive subsequent broadcast frames, and also
After turning off, a unique frequency signal is sent as an acknowledgment. When the switching device 10 detects the response A and the response B using the frequency detectors 13a and 13b, it transmits the broadcast frame and then sends a message to the terminal devices A and B using a frame FRAME・E(A,B) to indicate that the frame transmission is to be terminated. It is transmitted to the terminal device and RS is turned off. When terminal devices A and B receive FRAME・E (A, B), they confirm that the broadcast frame has been received normally, and transmit the frequency signal specific to the terminal device to exchange device 1.
0 as a confirmation response.

As explained above, in the branch line communication system, the present invention has means for transmitting a plurality of terminal devices simultaneously, and the terminal devices have means for transmitting a response signal of a unique frequency. Further, by configuring the switching device to have a means for receiving and identifying a frequency unique to the terminal device, the time required to confirm the broadcast can be shortened and the confirmation sequence can be avoided from becoming complicated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a switching device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a terminal device according to an embodiment of the present invention. 10...Switching device, 11...Line compatible device, 1
2... Frequency discrimination device, 13a, 13b, 13
c, 13a', 13b', 13c'...terminals A, B,
Frequency detectors corresponding to C, A′, B′, C′, 14
...Control information transmitter, 15...Communication control device, 1
6...Central processing unit, 20A, 20B, 20C,
20A', 20B', 20C'...Terminal devices A, B,
C, A', B', C', 21...Line compatible device, 22
...Response information transmitting unit, 23a, 23b...Signal sending unit of terminal devices A and B, 24...Communication control device,
25...Central processing unit, 26...Peripheral device. FIG. 3 is a diagram showing an example of the operation sequence of the embodiment of the present invention. FRAME・S(A,B)...Information frame for notifying the start of broadcast communication from the switching device to terminal devices A and B, response A...Confirmation response from terminal device A to the switching device, response B ...Confirmation response from terminal B to switching equipment, broadcast frame...Information frame for broadcasting from switching equipment to terminal equipment, FR-AME・E(A,B)......From switching equipment to terminal equipment A , B to notify the end of broadcast communication.

Claims (1)

[Claims] 1. In a data exchange network having a branch line into which a plurality of lines branch, and including a switching device and a plurality of terminal devices connected to the switching device via the branch line, a plurality of terminal devices are controlled simultaneously. The switching device is equipped with means for transmitting control information and means for receiving and discriminating multi-frequency signals, and transmits a unique frequency signal corresponding to each of the terminal devices connected to the branch line from the branch line. Each of the terminal devices includes means for transmitting and means for recognizing the control information transmitted from the exchange device, and when the terminal device recognizes the control information, a frequency signal unique to the terminal device is used as confirmation information. A branch line communication method characterized in that the information is transmitted to the switching device side as a branch line.