JPH02188042A - Loop type transmission line communication system - Google Patents

Abstract

PURPOSE:To eliminate the need to fix a master station and to enable an optional station to serve as a master station by allowing a terminal which calls first to operate as a one-side terminal (master station) in 1:N communication. CONSTITUTION:When a station C requests calling, the station C becomes the master station of 1:N communication from this point of time and send its station data a control signal to a transmission line. Consequently, a master station A detects the call of another station by a detecting circuit 3 and a control circuit 2 stops the retransmission of a control signal, etc., from its station with a control signal from the detecting circuit 3 to enter a through state. When a slave station B answers in the state of general calling from the master station C changed from the through state, the slave station B sends out an answer signal in synchronism with the transmission of data to the transmission line. Consequently, the slave station B is allowed to answer preferentially and the stopping and branching operation for calling another station are maintained and controlled. Here, only the answer signal is put in the through state at the station C in this case.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a communication system for a terminal device connected to a loop-type transmission line, and particularly to a communication system for a voice terminal device (1:N (N is a positive integer of 2 or more)). Regarding communication methods.

[Conventional technology]

Conventionally, 1:N communication in voice terminal equipment on this type of loop-type transmission path has generally been based on one-way communication such as simultaneous broadcasting, and even in the case of two-way communication, there is no response to simultaneous calls from the master station. , only the slave station that responded can do this.

[Problem that the invention seeks to solve]

By the way, in the case of the above-mentioned two-way communication in the conventional N communication, there is a problem in that the number of master stations that perform simultaneous paging is always limited.

An object of the present invention is to provide a communication system in which the master station is not limited.

[Means for solving problems]

In the 1:N communication method in the loop type transmission line of the present invention,
When the slave stations in the loop receive a simultaneous call from the master station, only the slave stations that respond send the data from their own station to the transmission path, and send the response signal back to the master station, allowing 1:1 bidirectional communication. In addition to the first control circuit that performs this control, there is also a monitoring circuit that monitors on/off hook information (hereinafter referred to as CD signal) flowing on the transmission path, and controls whether or not to return data on the transmission path using the CD signal. It is characterized by having one station having a second control circuit.

〔Example〕

Next, two examples of the present invention will be explained.

Generally, in conventional communication systems in which multiple stations are connected in a loop, a predetermined station is set as the 1 side (hereinafter referred to as the master station) of 1:N communication, and from this master station to the N side (hereinafter referred to as the master station). When a call is made to a slave station (slave station), only the slave station that responds sends data to the transmission path and sends a response signal back to the master station, thereby performing 1:1 bidirectional communication. .

Here, FIG. 2 shows an example of a data communication state in a loop type transmission line. As shown in Figure 2-(1), when there is no communication, station 2 is the quasi-master station (hereinafter referred to as sub-master).
It functions as a terminal and controls the termination of control signals flowing on the transmission path and the delay correction of data within the loop. The other stations (slaves) ■, ■, ■ perform only branching of data on the transmission path. At the submaster station, the data is terminated, and after passing through a delay correction circuit, which will be described later, is output to the transmission line.

As shown in FIG. 1-(1), the submaster ■ has branch/add circuit 1. A control circuit 2 that performs data control, a response signal detection circuit 6 that detects a response signal, and a call detection circuit 4 that detects a call from the own station. Receive buffer 1 circuit5. Transmission buffer circuit 6. Delay correction circuit that makes the data delay in the loop an integral multiple of the frame7. It also includes a detection circuit 8 that detects calls from higher-level stations on the loop, branches data and control signals to its own station, and retransmits control signals and the like. Further, in FIG. 1-(1), the data transmission path is indicated by a broken line.

As shown in Figure 1-(2), each slave has a branch
Insertion circuit 1. A control circuit 2 that performs data control, a response signal detection circuit 3 that detects a response signal, and a call detection circuit 4 that detects a call from the local station. Receive buffer circuit 5. and a transmission buffer circuit 6, and the data transmission path is shown by a broken line.

Here, when station 2, for example 9, issues a call request, station 2 becomes the master station for N communication from this point on, and sends its own data and control signals to the transmission path. As a result, the detection circuit 6 of the system master station detects a call from another station,
By inputting the control signal from the detection circuit 3 to the control circuit 2, the control circuit 2 stops retransmitting control signals etc. from its own station, and enters a through state. This state becomes a state of simultaneous calling from the master station (2) (shown in FIG. 2-(2)).

When the slave station (2) responds in this general paging state, the slave station (2) transmits a response signal along with sending data to the transmission path. As a result, priority is given to the response of the slave station (2), and calls to other stations are stopped and branch operations are maintained and controlled. However, in this case of waste removal (3), only the response signal is in a through state (this state is shown in FIG. 2-(3)).

That is, in the state shown in FIG. 2-(2), data and control signals from the second station (2) cause all other stations to be simultaneously called. At this time, the submaster station (3) detects a call from the higher-level station, stops accessing data from its own station, and enters a multi-drop state, thereby forming a loop. At this time.

A delay correction circuit is inserted.

In the state shown in Figure 2-(3), the response from the second station ■ will cause the station ■
Then, the response signal is set to a through state, and all calls are stopped at other stations and data lock control is performed, thereby forming a 1:1 bidirectional communication line between the stations 1 and 2.

〔Effect of the invention〕

As explained above, in the present invention, since the terminal that first makes the call becomes the 1-side terminal (master station) in 1:N communication, there is no need to fix the master station, and any station can call the master station. You can become a station.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the main parts of a submaster station and other stations constituting the present invention. FIG. 2 is a diagram for explaining a data communication state in a loop type transmission line according to the present invention. 1... Branch/insertion circuit, 2... Control circuit, 3...
Response detection circuit, 4... Call detection circuit, 5... Receiving bar. 6... Transmission buffer circuit, 7... Delay correction circuit, 8... Detection circuit. Figure 2-(1) Rumon

Claims (1)

[Claims] 1. Multiple terminal stations connected to a loop type transmission line are 1:N
A means for controlling the first station to make a call based on on/off hook information as a master station for 1:N communication, which is used when carrying out communication, and when the master station calls other stations all at once; The slave station that responded has a means for sending a response signal indicating the response to the transmission line, and only the slave station performs 1:1 bidirectional communication with the master station. A loop-type transmission line communication method.