JPS6034862B2 - Data terminal accommodation method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a terminal accommodation system in a data exchange network.

Accordingly, as a method of accommodating data terminals in a data exchange network, as shown in FIG.
2 via the DTE-OCE interface line 11. An in-office line termination device (DC
ES) 14, and each line is connected to a line concentrator (LC) 15.
Generally, subscriber lines connected to 3. etc. are carried at a certain bearer rate. Fox b/s, 6.4Kb/s, 1
2. A bearer rate of 6 b/s and 6 b/s is determined. Furthermore, the bearer rate is 8/6 times the sampling rate for start-stop terminals, and 8/6 times the terminal rate for synchronous terminals. This is because bits called F bit and S bit for enveloping are added, making it a 612 envelope format. The bearer rate is uniquely determined for each terminal speed, and one DCE has the disadvantage that only one terminal can be handled. SUMMARY OF THE INVENTION An object of the present invention is to provide a data terminal accommodation system that solves the above-mentioned drawbacks.

In order to achieve the above object, the present invention changes the code format on the subscriber line from bipolar to a code format that can withstand zeros, such as die-phase or NRZ, and changes the F bit pattern to 1010.
It is characterized by making it possible to accommodate a plurality of terminals with one DCE by using a bit format that spans three or more different envelopes.

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

FIG. 2 is a block diagram showing one embodiment of the present invention. 2
0 is a modification of the DCE shown in FIG. 12,
This is a device that accommodates multiple terminals, multiplexes them, and sends and receives them to one subscriber line.

Naturally, the speed (bearer rate) on the subscriber line is as high as the number of terminals accommodated at each terminal speed. For example, if four 1200 b/s terminals are accommodated, the bearer rate on the subscriber line is 6.4 Kb/s, which corresponds to the terminal speed of 4800 b/s. Reference numeral 21 denotes a line termination device within the station, which has a function of dividing this into four terminals if four terminals are multiplexed on the subscriber line.

Next, we will explain the envelope on the subscriber line. Figure 3 shows the format of the envelope on the normal subscriber line. The F bit pattern is transmitted by repeating 1010... Identifies the delimiter.

FIG. 4 shows an example of an envelope format on a subscriber line according to the present invention, in which the F bit pattern is 110
The data of the four subscribers can be identified by repeating 01100....

That is, #IA, #IB, #IC, and #ID can be distinguished by F-bit pattern detection. In this case, it is also possible to identify the boundaries of the envelope as well as the repetition of 1010. Also, at this time, there is a possibility that there will be consecutive 0s, so if a bipolar signal is used, it may become impossible to reproduce the signal, so a die-phase code, etc., which can always extract the clock signal, is used. There is a need. FIG. 5 is a block diagram showing the configuration of the device shown at 20 in FIG.

For example, assume that the data terminal is 1200 b/s. 30 is a circuit that multiplexes four pieces of 1200 b/s data, and 31 is a circuit that transmits or receives data onto the subscriber line at a bearer rate of 4800 b/s→6400 b/s.

32 is a circuit consisting of an F bit pattern detection circuit and counters for identifying four subscribers.

In this way, when a certain number of terminals exist on the subscriber side, multiplexing in the DCE section makes it possible to reduce the number of lines and the number of DCEs. As explained above, the present invention makes the code format on the subscriber line a code format that can withstand consecutive zeros, and makes the F bit pattern a pattern that spans three or more envelopes.
This has the effect of accommodating multiple terminals on a subscriber line.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional terminal accommodation method in a data exchange network, FIG. 2 is a block diagram showing a terminal accommodation method of the present invention, and FIG. 3 is a diagram showing a conventional envelope format on a subscriber line. FIG. 4 is a diagram showing the envelope format on the subscriber line according to the present invention, and FIG. 5 is a block diagram showing one configuration of the reproducing portion of the present invention. 10...Data terminal (DTE), 11...
Interface line, 13...Subscriber line, 15.
...Line concentrator (LC), 12, 20, 21...
・Line termination device, 30... Multiplexing circuit, 31.
...Bearer rate conversion circuit, 32...Identification circuit. Figure 2*4. diagram that originates

Claims (1)

[Claims] 1. In a system in which data is transmitted in a 6+2 envelope format on each subscriber line in a data switching network, the pattern of F bits in the envelope is different from 1010 repetitions.
A data terminal accommodating system characterized by accommodating a plurality of subscribers on one subscriber line by configuring repeating bits that span the above envelope.