JPS59100656A - Hand shake transmitting system - Google Patents

Abstract

PURPOSE:To reduce the communication time and to attain efficient communication by substituting a repeater for a part of commands and responses transmitted and received between stations functioning as a talker and a listener. CONSTITUTION:Switching circuits SW1-SW6 of repeaters R1, R2 are connected to the 1st contact 1 at the start of data transmission and the transmission by a hand shake system is executed. In performing the data transmission of the 1st cycle, the switching circuits SW1-SW6 are changed over to the 2nd contact 2. A control circuit CT1 of the repeater R1 responds to the command signal transmitted from the station functioning as a talker in the 2nd cycle. Further, a control circuit CT2 of the repeater R2 transmits a command signal to the station functioning as the listener and receives a response signal from the station functioning as the listener. Thus, the transmittion and reception of the command and the response signal are not transmitted for a long section and only data D on a bus line is transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data transmission system between information processing devices or between a main device and a slave device of information processing devices. especially,
The present invention relates to a data transmission method that sends and receives data via a transmission path using a handshake method.

The handshake method is a system in which a means for transmitting control signals is attached to the transmission path for transmitting data, and a command signal is transmitted from a station that is a talker that transmits data to a station that is a listener that receives data. In response to a command signal, a station serving as a listener sends and receives data over a transmission line while returning a response signal to a station serving as a listener depending on its state. The transmission path for the control signal can be provided space-divisionally or time-divisionally with respect to the transmission path for transmitting data.

The handshake method is widely used because it is an excellent method that allows devices with different response speeds to be connected to a common transmission path and ensures extremely reliable data transmission and reception. On the other hand, as the distance between stations increases,
The method used is to extend the transmission path by inserting a repeater into the transmission path, but when the huntshake method is performed between stations connected by such a long transmission path, the command and response signals are The disadvantage is that the transmission time becomes longer and the data transmission efficiency decreases.

The present invention is an improvement on this, and is a method in which a repeater is inserted into the transmission path and communication is performed by a handshake method via a long transmission path, thereby shortening communication time and achieving efficient communication. The purpose is to provide a method that allows

The present invention provides a repeater inserted in a transmission path with a means for receiving commands and responses based on the huntshake method and transmitting corresponding responses or commands, and transmitting and receiving the commands and responses between both stations based on the huntshake method. The present invention is characterized in that the repeater is configured to issue some commands and responses instead.

Also, in the first and last cycles of a large number of continuous data transmission cycles, commands and responses are performed using the normal handshake method, and in other cycles, the repeater takes over the commands and responses using the handshake method. can be configured to do so.

Roughly speaking, it is possible to configure the repeater to perform commands and responses based on the hunt shake method in cycles other than a predetermined cycle among a large number of consecutive data transmission cycles.

This will be explained in more detail using the drawings.

FIG. 1 is a time chart showing the procedure of handshake data transmission. DAT^ indicates the timing of data sent on the path line from the station serving as a talker. A command signal is sent from the talker station to the listener station on the signal line 8v (LID to lAT8V).

Signal 1 spring NRFD (NOT RADY FORDAT
8) and NDAC (DATA NOT ACT), a response signal is transmitted from the listener station to the talker station. When the talker station sets the signal line DAV to logic "1", the listener station responds by setting the signal line 11RFD to logic "1". The talker station that receives this changes the signal line DAV to logic "1" if the data being sent to the pass line at that time is to be valid. The station serving as a listener takes in the data on the path line and sends a logic "1" to the signal line NDAC. In the stage signal that receives this and becomes the talker, the signal line DA
Send a logic "1" to V and move on to the next cycle.

In this way, in the handshake method, data is transmitted while transmitting and receiving control signals in one cycle.

FIG. 2 shows a configuration in which the transmission path between station T, which serves as a talker, and station R, which serves as a listener, is extended and repeaters R1 and R2 are inserted.

When handshake transmission is performed with this configuration,
The procedure is shown in Figure 3. Since FIG. 3 can be understood in the same way as FIG.
Since the communication goes through a long transmission path, the communication time for one cycle becomes long.

FIG. 4 is a block diagram of the main parts of the first repeater R1 according to the embodiment of the present invention. A station serving as a talker is connected to the left side of the figure via a short transmission path.

On the right side of the figure, a second repeater R2 is connected via a long transmission path, and a station serving as a listener is further connected beyond that.

The data signal of the lotus line D is relayed by a relay circuit Rpo. The signal line DAV from the talker side is the switching circuit SWx
The relay circuit Rp is connected to the first contact 1 and not connected to the first contact 1.
, and the control circuit CT1 connected to the second contact 2. The signal line NRFD from the listener side is connected to the input of the relay circuit Rp2, and its output is sent to the signal line NRFD on the talker side via the first contact 1 of the switching circuit Sl'I2. Further, the signal line NDAC from the listener side is connected to the input of the relay circuit Rp3, and its output is sent to the signal line NDAC on the left side of 1.- via the first contact 1 of the switching circuit SW3. The switching circuit SWz and the switching circuit needle 3 are the switching circuit Sl'li.
This switching circuit needle 1 to 5II
I3 is remotely controlled from a station serving as a talker by means not shown.

The control circuit CTi is the same as the response command circuit provided in the handshake type station, and the data reception confirmation input is set to a pseudo logic level of confirmation.

FIG. 5 is a block diagram of the main parts of the second repeater R2 according to the embodiment of the present invention. On the left side of the figure, a first repeater R1 is connected via a long transmission line, and a station serving as a talker is further connected beyond that.

On the right side of the figure, a station serving as a listener is connected via a short transmission path.

The data signal on pass line D is relayed by relay circuit Rpo'. The signal line DAV from the talker side is relay circuit R
1) It is connected to the first contact 1 of the switching circuit SW-+ via 4, and is connected to the signal line DAV from the listener side via this switching circuit SW+. Signal line NRFD from listener side
is connected to the switching circuit needle 5. The first contact 1 of the switching circuit STo is connected to the input of the relay circuit Rp5, and its output is sent to the signal line NRFD on the talker side. Further, the signal line NDAC from the listener side is connected to the S corner of the switching circuit.

The first contact 1 of the switching circuit SWs is connected to the input of the relay circuit Rpe, and its output is sent to the signal line NDAC on the talker side. The second contacts 2 of the switching circuits SWs and SWe are connected to the human power of the control circuit CT2, and the output of the control circuit CT2 is connected to the second contact 2 of the switching circuit SW4. The switching circuit SW2 and the switching circuit section 3 are configured to operate in conjunction with the switching circuit 1, and this switching circuit Sl'h
~SW3 is remotely controlled from a station serving as a talker by means not shown. The control circuit CT2 is the same as the response command circuit provided in the handshake type station, and the data reception confirmation input is set to a pseudo-confirmed logic level.

It is preferable to provide a separate control signal line for the control means of the switching circuits SWt to S'/I6, but if this is not appropriate, the signal can be multiplexed onto other control lines or data lines and transmitted. .

To explain the operation of the device configured in this way, at the beginning of data transmission, the switching circuits SWx to SWs of each repeater R1 and R2 are connected to the first contact 1. In this state, the talker and listener are in a transparent state and can perform transmission using the handshake method as in the conventional method. When one cycle of data transmission is performed in this state, the switching circuits SWi to Slk are switched to the second contact 2. In the second cycle, the control circuit C'h of the repeater R1 responds to the command signal transmitted from the station serving as the talker. Also, repeater R
The second control circuit CT2 transmits a command signal to a station serving as a listener, and receives a response signal from the station serving as a listener. Therefore, the command signal and response signal are not transmitted over the long transmission line section, and only the data D on the path line is transmitted.

Data transmission is performed n consecutive times, and at the final cycle, the switching circuits SWt to SW6 are switched to the first contact l. As a result, the station serving as the talker and the station serving as the listener become transparent again, and signals are directly transmitted and received using the handshake method. At this time, if the data to be transmitted is indeed from the final cycle, it can be seen that the data was transmitted correctly even in the intermediate cycles. In this final cycle, it is also possible to transmit an acknowledgment of the data of n cycles from station 0, which is the listener, to the station which is the talker.

When the cycle of continuous data transmission is long, data reception can be confirmed by switching the switching circuits SWt to SW6 to the first contact 1 at an appropriately set short cycle.

FIG. 6 is a diagram showing a communication control procedure according to an embodiment of the present invention. The horizontal axis represents the length of the transmission path, and the vertical axis represents the passage of time. (2) 1 to In is a cycle of data transmission n times. Complete handshake transmission is performed only for the first and nth times, and data D is transmitted from the second to n-1th times.
only. The fine zigzags in the figure indicate handshake commands and responses between the repeater and the station.

FIG. 7 shows the communication control procedure of the conventional method using a similar diagram as a comparative example. A state in which a complete handshake command and response are executed in all n cycles is shown.

At this time, the signal propagation time of the short transmission path between the station and the repeater is T.

If the signal propagation time of the long transmission path between two repeaters is Tff, and the delay time due to the repeater regeneration operation is ignored, the communication time of one cycle is 4 (2To
+77, so the communication time for n cycles is T t −
4n (2T o + T R). On the other hand, when similar calculations are made using the method according to the embodiment of the present invention shown in FIG. 6, T t = 6 To + 2 T (1 + 4 (
n2) T.

+8To+2Tj2 -4 n T O+ 6 T o + 4 T 7! becomes. Long propagation time T7! Since the data is not multiplied by 0, the overall communication time can be significantly reduced.

The present invention is suitable for implementation in an optical communication system using an optical fiber as a transmission path.

In the above example, the number of stations serving as talkers and stages serving as listeners was 1111 each, but the transmission path was a pass line, and a large number of stations were connected to this pass line, and 1/II of these stations became talkers at any time, and others The present invention can be similarly implemented in a system in which one or more of the following are listeners.

The above example describes an example in which there are three control signal lines for handshake, but the control signal lines are not limited to this type.
The invention can be implemented in a variety of formats.

As described above, according to the present invention, the communication time can be shortened and the communication efficiency can be improved without changing the station equipment.

[Brief explanation of the drawing]

FIG. 1 is a time chart illustrating handshake type communication control operation. FIG. 2 is a configuration diagram showing a configuration in which a repeater is inserted into a transmission path. FIG. 3 is a time chart explaining the communication control operation. FIG. 4 is a configuration diagram of the first repeater R1. FIG. 5 is a configuration diagram of the second repeater R2. FIG. 6 is a diagram illustrating the communication control operation of the embodiment of the present invention. FIG. 7 is a diagram illustrating a conventional communication control operation. T... Station that serves as a talker, L... Station that serves as a listener, R1, R2... Repeater. , c ′ 4 6th 7th Fig.

Claims (3)

[Claims] (1) It is equipped with a station that serves as a talker, a station that serves as a listener, and a transmission line that connects the above two stations, and a repeater is inserted into this transmission line to extend the above transmission line, and between the above two stations. In a method configured to perform data transmission by a handshake method via the transmission path, the repeater is provided with means for receiving commands and responses by the handshake method and transmitting corresponding responses or commands, 1. A handshake transmission method characterized in that a Juki repeater is configured to perform some of the handshake commands and responses to be transmitted and received between both stations on behalf of both stations. (2) The handshaking system according to claim 11, in which the repeater performs commands and responses based on the handshake method in cycles other than the first cycle and the last cycle among a large number of consecutive data transmission cycles. Shake transmission method. (3) Claim (1) in which the repeater performs commands and responses using the handshake method in cycles other than a predetermined number of cycles among a large number of consecutive data transmission cycles. The handshake transmission method described in section.