JPS5854697B2 - 2-wire digital subscriber equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In digital communication using a time-division direction control type transmission system, the present invention converts information transmitted on a two-wire line into information on a four-wire transmission line, and also performs line concentration and multiplexing in a time-division manner. or to subscriber equipment that can be replaced.

One of the methods for transmitting digital bidirectional information over a two-wire line
One of them is the time-division direction control type transmission system (for example, refer to the Institute of Electronics and Communication Engineers communication system study group material "Study on the method of configuring an all-digital telephone subscriber system" C378-20).

FIG. 1 is a diagram showing the configuration of this conventional time-division direction control type transmission system, where 1 is a connection terminal with a two-wire line, and 2 is a balanced terminal for connecting the two-wire line and the four-wire line. An unbalanced conversion transformer, 3 is a 4-wire side transmission information input terminal, 4 is a 4-wire side reception signal output terminal, 5 is a transmitter that sends a signal to the 2-wire line through the transformer 2, and 6 is a transmitter that transmits information on the input terminal 3. A transmission temporary storage device temporarily stores the signal and sends it to the transmitter 5; T is a receiver that receives the signal from the two-wire line from the transformer 2; 8 temporarily stores the signal from the receiver 7 and sends it to the output terminal 4. This is a receiving temporary storage device for sending out data.

FIG. 2 is a timing diagram for explaining the operation of FIG.
is the input signal to input terminal 3, B is the 2-wire line connection terminal 1
C is the output signal of output terminal 4, Tf
is the frame period, Tb is the burst period, 5i (i=o,
1, 2, 3) are transmitted signals separated by the frame period Tf, and Ri (i=o, 1, 2, 3) are received signals separated by the frame period Tf.

A conventional transmission system will be explained using FIG.

Suppose now that nKb/s is being transmitted and nKb/s is being received at the same time.

The transmission signal at the input terminal 3 is divided into blocks Si every frame period Tf, and written into the transmission temporary storage device 6.

The written data is successively output from the storage device 6 at a speed faster than 2n (speed = 1/TB), and from the transmitter 5 to the 2n.
It is sent to the wire line terminal 1.

The receiving operation is performed in the reverse manner.

In this way, bidirectional transmission using a two-wire line becomes possible.

In this conventional technology, the input and output signals of terminals 3 and 4 have a speed of < nKHz as shown in Figure 2 A and C, so when multiplexing these signals, the data speed must be converted again to the required speed. For example, operations such as serial-to-parallel conversion, multiplexing, and parallel-to-serial conversion are required.

In order to enable concentrating or exchanging operations as needed on a four-wire line, this invention matches the reading or writing speed of the transmitting or receiving two-way storage device to the speed required for concentrating, multiplexing or exchanging lines, and furthermore, two The frame period is also different from the frame structure on the formula line, and reading is performed at an arbitrary time position within the frame or writing is performed from that time position.

FIG. 3 shows an embodiment of a subscriber device according to the present invention,
9 is a write address designation circuit for the transmission temporary storage device 6, 10 is a read address designation circuit for the reception temporary storage device 8, and the other 1 to 8 have the same reference numerals as in FIG.

FIG. 4 is a timing diagram for explaining the operation of the device shown in FIG. 3, where A is the input signal to input terminal 3, B is the signal at two-wire line terminal 1, and C is the output at output terminal 4. signal,
Tg is the frame period at terminals 3 and 4, ki (i = 1 to 5
) is the time slot number constituting the frame at terminals 3 and 4 (in this case, there are 5 time slots from 1 to 2, but this is a convenient number for explanation, and any number of time slots can be used) ) Other symbols are the same as the same symbols in FIG.

The embodiment shown in FIG. 3 will be explained using the operation timing shown in FIG. 4.

If the frame period Tg at the terminals 3 and 4 of the 4-wire system and the frame period Tf at the terminal 1 of the 2-wire system satisfy the relationship of rational numbers, the amount of information in and out will be the same for each frame period of the least common multiple. By placing a temporary storage device corresponding to the amount of information in the transmitter/receiver unit, information can be stored without any loss or surplus.
It is possible to propagate between the wire terminal 1 and the four-wire terminals 3,4.

Now, consider a situation in which information for two time slots on a frame at terminals 3 and 4 is transmitted to or received from terminal 1.

Information arriving from the terminal 1 for each frame configuration, for example, signals R1+R2, is temporarily stored in a temporary storage device 8 via a receiver 7.

The addressing circuit 10 uses this temporarily stored information as
Signal R1 is read out at two time slot positions in a Tg period, and signal R2 is read out in the next Tg period.

Conversely, two pieces of information S1 . S2 is sequentially written into the temporary storage device 6 by the addressing circuit 9 at two time slots, and the information is read out from the temporary storage device 6 two at a time at the Tf period.

By repeating this operation, information located at an arbitrary time slot on the frame at the 4-wire terminals 3 and 4 and 2
Connection with the wire transmission line terminal 1 becomes possible.

Here, the addressing circuits 9 and 10 may be installed independently, or they may be shared.

As explained above, according to the present invention, the frame length on the 2-wire line of the 2-wire subscriber line transmission system and the frame length on the 4-line side can be made different, and any Since time slot information can be sent and received on the 2-wire line, this effect can be used to multiplex the information on the 4-wire side.
When operations such as line concentration and exchange are performed by time division multiplexing, direct access to the temporary storage devices 9 and 10 enables the multiplexing, line concentration and exchange operations.

Further, as a result, there is an advantage that when performing multiple line concentration, there is no need to convert the data rate to a required rate.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional time-division direction control type transmission system, FIG. 2 is a timing diagram showing an example of the operation of FIG. 1, and FIG. 3 is an implementation of a two-wire digital subscriber device according to the present invention. A configuration diagram showing an example, and FIG. 4 is a timing diagram showing an example of the operation of FIG. 3. 1: Connection terminal with 2-wire line, 2: Balanced-unbalanced conversion transformer, 3: 4-wire side transmission information input terminal, 4: 4-wire side received signal output terminal, 5: Transmitter, 6: Transmission temporary memory device, 7
: Receiver, 8: Reception temporary storage device.

Claims (1)

[Claims] In a digital subscriber device that transmits and receives 4-wire digital information via a 12-wire line, there is a transmission-side temporary switch that converts the speed of the 4-wire side transmission information at regular intervals and sends it to the 2-wire line. a storage device, a reception side temporary storage device that converts the speed of the 4-wire side reception information received from the 2-wire line to the 4-wire side at regular intervals and sends it out; a read addressing circuit that divides the frame and reads it into a specific channel of a frame with a multi-channel configuration on the 4-wire side; a write addressing circuit that writes a specific channel of the frame with a multi-channel configuration on the 4-wire side to a temporary storage device on the sending side; A two-wire digital subscriber line system equipped with