JPS63217742A - Line exchange loop network - Google Patents

Abstract

PURPOSE:To attain high speed transmission by denoting the length of frame by a specific length and assigning a data signal and control signal for data transmission by handshake to a part of a frame. CONSTITUTION:A line exchange loop network is provided with a loop transmis sion line 1, a node station 2 on the transmission line 1 and transmission/ reception terminal equipments 3, 4 connected to the station 2. Through the constitution above, in case of applying data transmission to the transmission/ reception terminal equipments according to the hand shake procedure in the circuit exchange loop network where a frame is circulated periodically, the length of the frame is denoted by 125/nmus (n is an integral number). Thus, the time of a channel circulated once through the line 1 is 125/nmus. The channel consists of a data channel and a control information part. The terminal equipments 3, 4 use the control information and send the control information for hand shake. The sent time is reduced to 125 nmus, by a factor of n.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to circuit switched loop networks.

[Prior Art] When sending digital data from a transmitting device to a receiving device,
A technique called handshake is commonly used. An example is shown in FIG. As shown in the figure, the transmitting side lowers the 5END line to L as a signal that data has been sent. On the receiving side, when the 5END line goes low, it starts reading data, and when this is completed, the REC
Lower the line to L. On the transmitting side, when RECD falls to L, SEND is returned to H to prepare for sending the next data. On the receiving side, when 5END returns to H, it raises RECD to H and prepares to receive the next data. Handshaking is a method for ensuring data exchange, and the data transmission speed cannot be determined in part. That is, if a device with a slow data processing speed is used, the time for one cycle shown in FIG. 2 will be long, and the transmission speed will be low. On the other hand, if a device with a fast data processing speed is used, high-speed transmission will be possible.

G is known as a general-purpose interface between measuring instruments.
PIB is a standard for exchanging data by handshaking between a transmitting device and multiple receiving devices, and when infinitely fast devices are connected, transmission up to IM bytes/second is possible.

On the other hand, with the spread of OA and FA in recent years, there has been an increasing demand for networks that can transmit not only data transmission but also voice data such as telephone calls, and circuit-switched loop networks are attracting attention as a solution that can meet this demand. FIG. 3 shows an example of its configuration. As shown in the figure, the circuit-switched loop network includes a loop transmission line 1, a node station 2 provided on the transmission line 1, and transmitting and receiving terminals 3, 4, etc. connected to the node station 2. . A frame 5 as shown in FIG. 4 periodically circulates on the transmission line 1. Frame 5 consists of a plurality of divided channels, and transmission between terminals is performed through these channels. The frame length is generally 125 μS considering audio data.
ec. Normally, one channel (8 bits of data) allows transmission at a maximum of 64 Kbps.

Now, let us consider the case where a terminal that sends and receives data by handshaking is connected to a circuit-switched loop network and data is transmitted. In this case, in addition to data, control signals for handshaking also need to be transmitted through the transmission path.

[Problems to be Solved by the Invention] In the circuit-switched loop network described above, each control signal requires at least 125 μS, which is equal to the frame length, to be sequentially transmitted from the transmitting terminal to the receiving terminal and then to the transmitting terminal. In a system like the one shown in Figure 2 above, in which control signals are exchanged twice in one transmission, the maximum transmission speed is 32 Kbps, assuming that 8 bits are transmitted in one data transmission.
It reaches only up to (8/125×2μS). Therefore, even if the terminal is capable of high-speed response, the transmission speed is limited on the network side, and there is a problem that high-speed transmission cannot be performed.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a circuit-switched loop network that enables high-speed transmission for communications that transmit and receive data using handshakes. be.

[Means for solving the problem] The above purpose is to reduce the frame length to 125/nμS when transmitting and receiving terminals are connected to a terminal that performs data transmission by handshaking between them. This is achieved by allocating and transmitting data signals and control signals for data transmission by handshaking to a part of the frame.

[Operation] When transmitting and receiving terminals are connected to a terminal that performs data transmission by handshaking between these terminals,
The length of the frame is 125/nμS, and the data signal and control signal for data transmission by handshake' are allocated to a part of the frame for transmission, so the transmitting terminal and receiving terminal use this control signal. However, the time it takes for the control information to be transmitted from the transmitting terminal to the receiving terminal to the transmitting terminal is 125/nμS. Therefore, the transmission time is 1
/ can be shortened to n.

[Example] The present invention will be described below based on the illustrated example. FIG. 1 shows an embodiment of the invention. Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, when transmitting and receiving terminals are connected to a terminal that performs data transmission by handshaking between these terminals, the length of the frame 5a is set to 125/nμS,
Data signals and control signals for data transmission by handshaking are allocated to a part of the frame 5a for transmission. By doing this, it became possible to perform high-speed transmission for communication that uses handshaking to send and receive data, and a circuit-switched loop network that enabled high-speed transmission for communication that uses handshake to send and receive data. can be obtained.

That is, as shown in Fig. 3 above, in a circuit-switched loop network that includes loop transmission lines, node stations, transmitting and receiving terminals, and in which frames circulate periodically, data is transferred between the transmitting and receiving terminals through a handshake procedure. When transmitting, the length of the frame is set to 125/nμS (n: integer), so the time it takes for the channel to make one revolution on the loop transmission path is 125/nμS. The circuit switched loop network then allocates one channel for communication between the sending and receiving terminals. The structure of the channel consists of 8 bits of data and a control information section, similar to the conventional channel. The transmitting terminal and the receiving terminal use this control information section to transmit control information for handshaking. At this time, the time required for the control information to be transmitted from the transmitting terminal to the receiving terminal and the transmitting terminal is reduced to 125/nμS, which is 1/n of the conventional method.

As described above, according to this embodiment, the time for transmitting the control signal can be reduced to 1/n (n: integer) of the conventional method. Therefore, the maximum transmission speed of the circuit switching loop network for communication between terminals that performs data transmission by handshaking can be increased n times compared to the conventional method.

[Effects of the Invention] As described above, the present invention enables high-speed transmission for communication in which data is sent and received by handshaking in a circuit-switched loop network; A circuit-switched loop network that enables transmission can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the frame structure of an embodiment of the circuit switched loop network of the present invention, FIG. 2 is a signal flow diagram showing an example of handshake, and FIG. 3 is a diagram showing the configuration of the circuit switched loop network. FIG. 4 is an explanatory diagram showing the structure of a frame of a conventional circuit switching loop network. 1: loop transmission path, 2: node station, 3: transmitting terminal, 4: receiving terminal, 5a: frame.

Claims (1)

[Claims] (1) A frame comprising a loop transmission path, a node station provided on the loop transmission path, and transmitting and receiving terminals connected to the node station, and having a plurality of divided channels on the loop transmission path. In a circuit-switched loop network in which the frame is periodically circulated, when transmitting and receiving terminals are connected to a terminal that performs data transmission by handshaking between them, the length of the frame is set to 125. /nμS, and data signals and control signals for data transmission by handshaking are allocated to a part of the frame for transmission.