JPS596649A - Repeating device of data - Google Patents

Abstract

PURPOSE:To reduce the delay of data repeating and to reduce the cost of a cable and a data transmitting/receiving circuit, by accumulating data and adding a synchronization maintaining sequence in accordance with the phase difference between a synchronizing signal in receiving data and that in an MODEM. CONSTITUTION:The phase difference between a synchronizing signal extracted 44 from data received from a terminal device 3 and the synchronizing signal of the MODEM2 is detected, and when the number of synchronizing signals extracted from the data received from the terminal device 3 is larger than that of MODEM synchronizing signals, the data which can not be transmitted to the MODEM2 is stored in a bit buffer 48 of a repeating device 4 until the terminal device 3 sends an end character for a transmission massage. If the number of synchronizing signals of the MODEM2 is larger than the number of synchronizing signals extracted from the data received from the terminal device 3, the terminal device 3 sends a synchronization maintaining sequence, then the repeating device 4 adds a synchronization maintaining sequence moreover.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a relay device for relaying bit synchronization signals using a SYN synchronization communication procedure.

Prior Art When connecting multiple terminal devices to a terminal control device via a communication line, a modem 2 and a terminal device 3 are connected to the terminal control device 1 via a modem 2 and a communication line 5 in a multi-branch manner, as shown in FIG. things are being done. In this case: (a) Since each terminal device i3 must be connected to the modem 2, as the number of connected terminal devices increases, the number of modems also increases.

(b) Due to the multi-branch connection, each terminal device alternately controls the carrier output of the modem, resulting in a large transmission overhead. There are other problems.

Conventionally, in order to solve the above problem, a terminal control device 1, a modem 2, a communication line 5, and a terminal bag ff3 are connected via a data relay device 4 as shown in FIG. In this case, data relay (1
) There is a method in which a modem synchronization signal is supplied to the terminal device 3 and data transmission from the terminal device 3 is synchronized with the synchronization signal from the modem 2. in this case.

The signal cable between the data relay device 4 and each terminal bag f3 requires a cable for data transmission and a cable for transmitting synchronization signals, and the disadvantage is that the cost of the cable and the cost of the data transmission/reception circuit increase in proportion to the number of terminals connected. There is. 0) The data relay device 4 is equipped with a serial/parallel converter, a storage device, and a 10 setter, and the serial/parallel converter converts the serial data received from the terminal device 3 into a parallel take, and once stores it in the storage device, the terminal The method of transmitting data to the control device 1 in synchronization with the synchronization signal of the modem 2 has the drawback that the delay due to data relay increases and the cost of the data relay device increases because the signal is converted from serial to parallel.

OBJECT OF THE INVENTION The object of the invention is to solve the problems of the prior art.

General description of the invention 1 The present invention detects the phase difference between a synchronization signal extracted from data received from a terminal device and a synchronization signal with a modem.a) The number of synchronization signals extracted from data received from the terminal device is If the number is greater than the number of modem synchronization signals, the terminal stores the takes that could not be sent out to the modem in the bit buffer until it sends the end character of the message.

(2) When the number of synchronization signals from the modem becomes larger than the number of synchronization signals extracted from the data received by the terminal device, after the terminal device i sends the synchronization maintenance sequence, the relay device further maintains synchronization. It adds a sequence.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to FIGS. 3 and 4.

Reference numeral 4 in FIG. 6 is a data relay device according to the present invention, in which data received from the terminal device 6 is transferred to a receiving circuit 40 and an OR circuit 4.
1 and is extracted as a received signal 401. Note that in this data relay device f4, it is assumed that data is not transmitted from two or more terminal devices 3 at the same time. The received signal 401 is SYN
The detection unit 42 is supplied to an end character detection unit 46, a synchronization signal extraction unit 44, and a bit buffer unit 48. S.Y.
The N detection unit 42 uses a synchronization maintenance sequence (0011001
0)2, and the end character detection section 46 monitors the end of the message and reports the result to the control section 46.

The synchronization signal extraction unit 44 extracts the bit interval of the received signal 40101 by detecting the data change point of the received signal 401, and outputs the received data synchronization signal 402. Furthermore, the received signal 401 is 1 in synchronization with the received data synchronization signal 402.
Every time a bit is received, it is stored in the pit buffer unit 48. After the focus buffer section 48 stores the input data by a preset number of bits, the phases of the modem synchronization signal 403 and the modem synchronization signal 4030 are constantly compared by the phase comparison section 45. If one bit or more of the receive take synchronization signal 402 is detected while one bit of the modem synchronization signal 403 is detected, input to the pit buffer section 48-\ is performed in synchronization with the receive data synchronization signal 402, The extra data is stored by the difference between the number of input and output bits. At this time, when the end character detection section 43 detects the end of the message, the control section 46 prohibits data input to the pit buffer section 48 until the number of bits of data stored in the pit buffer section 48 reaches the initial setting value. do. The relationship between the received signal 401 and the transmitted signal 404 in the above case is explained in the fourth example.
Figure (a) shows K. (b) Receive data synchronization signal 402 to 1
If one bit or more of the modem synchronization signal 405 is detected during bit detection, the output from the pit buffer section 48 is
Since this is performed in synchronization with the modem synchronization signal 405, the number of bits of data stored in the pit buffer section 4B is reduced. At this time, when the SYN detecting section 42 detects a synchronization maintenance sequence, the S'YN insertion section 47 is operated to forcibly insert the synchronization maintenance sequence into the pit buffer section 48, thereby increasing the number of bits of stored data. The relationship between the received signal 401 and the transmitted signal 404 in the above case is shown in FIG. Note that in this method, a synchronization maintenance sequence is added after the synchronization maintenance sequence as shown in ) in Figure 4, but in the SYN synchronization communication procedure, even if multiple synchronization maintenance sequences are consecutive, there is no i time between the synchronization maintenance sequences. It does not affect the transmission of the frame part.

Although one embodiment of the present invention has been described above, the above embodiment can be implemented with further modifications.

For example, in the above embodiment, if there is no clock deviation, for example, if the received data arrives at a predetermined speed,
The SYN detection section 42 and the 8YN insertion section 47 are not necessarily required.

As another modification, the end character detection section 43 may not necessarily be provided.

Effect of the invention According to the present invention, the following effects can be obtained.

(a) Since it is not necessary to supply a modem synchronization signal to the terminal device, cable costs and data transmission/reception circuit costs can be reduced.

(b) Since this method does not perform serial-to-parallel conversion of serial data, there is little delay for data relay.

(C) Since no serial/parallel converter or processor is required, an inexpensive relay device can be realized.

[Brief explanation of the drawing]

1 and 2 are system configuration diagrams for explaining the prior art, FIG. 3 is a block diagram of a data relay device for explaining an embodiment of the present invention, and FIG. 4 is a time chart thereof. 1... Terminal control device 2... Modem 6... Terminal device 4... Data relay device 5... Communication line 4D... Receiving circuit 41... OR circuit 42.
...S"YN detection section 43...End character detection section 44...Synchronization signal extraction section 45...Phase comparison section 46...Control section 47...
- Me A insertion section 48... Focus 4727 section 49... Transmission circuit 401... Reception signal 402... Reception data synchronization signal 405... Modem synchronization key code 404... Transmission signal O 1 layer ′? 2 scolding

Claims (1)

[Claims] The terminal device is connected by a short-distance interface, and the terminal control device is connected by a long-distance interface via a modem, and the SYN between the terminal device and the terminal control device is
In a device that relays a bit synchronization signal based on a synchronous communication procedure, a SYN detection section detects a synchronization maintenance sequence (aallaolo) based on data received from a terminal device, and an end character detection section detects an end character of a message from the terminal device. a synchronization extractor that extracts the 1-bit interval of the received data; a phase comparator that compares the phase of the synchronization signal extracted from the synchronization extractor with the synchronization signal of the modem; The data input is performed in synchronization with the synchronization signal output from the synchronization extraction section, and the data output section is performed in synchronization with the modem synchronization signal in the pit buffer section and the synchronization maintenance sequence is inserted into the bit buffer section. SYN insertion section and (1) If 1 bit or more of data is detected from the terminal device while detecting 1 bit of modem synchronization signal, the number of delay bits in the pit buffer section is increased by the number of bits of the difference, and the process ends. By detecting the end character of the message in the character detection section, the number of delay bits in the pit buffer section is restored to its initial state; If received, the number of delay bits in the bit buffer is reduced by the number of bits of the difference, and when the SYN detection section detects a synchronization maintenance sequence, the SYN insertion section inserts the synchronization maintenance sequence into the bit buffer, and the inserted bit is 1. A data relay device, comprising: a control unit that increases the number of delay bits in a bit buffer by the number of bits.