JPH01179538A - Time-division multiplexing device - Google Patents

Abstract

PURPOSE:To improve the traffic efficiency by fetching a carrier detection CD signal into a buffer in the same timing RT as the timing RT fetching a received data RD into a buffer and sending the data RD, CD to an opposite time-division multiplexing device TDM while keeping the relation of time between the RD and CD from a low speed line. CONSTITUTION:In the case of fetching the RD from a low speed line into a buffer circuit 13 comprising a first-in first-out FIFO in the timing RT, the data CD is also fetched in the same timing RT. Then by an OR circuit 14, ORs data CD1 and CD extracted from the FIFO and gives the result as an HCD. That is, the circuit fetching the RD and CD into the buffer 13 acts like storing the RD and CD in the same time because of fetching of the same timing RT. Then the relation of the RD, CD is kept the same as that arrived from a low speed line and sent to the opposite TDM, then no effect is given onto the response.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a multiplexing and distribution device (hereinafter referred to as TDM) that time-division multiplexes data on a low-speed line onto a high-speed line, and particularly relates to carrier detection using multi-point connections. The present invention relates to a CD signal transmission method suitable for TDM when supporting a line that turns signals on and off.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 1988-88140, the conventional device uses a carrier detection signal (referred to as Tsutsukushita CD) and received data (hereinafter referred to as RD), which are generated due to a data delay caused by a buffer in the low-speed line compatible section of TDM. In order to prevent overlapping of CD-OFF information (hereinafter referred to as R8), a transmission request signal (hereinafter referred to as R8) or CD was turned off after counting the CD-off information by a certain number in the low-speed line support section of the other party's TDM. However, in contrast to the relationship between RD from the modem and CD off, there is a relationship between transmission data to the other party's modem (hereinafter referred to as SD) and R, S off, or a relationship between R, D and CD off to the other party's CCP. The conventional technology described above does not take into consideration the fact that the response time due to turning on and off the CD becomes longer.
In order to prevent RD and CD overlaps caused by data delays due to TDM buffers, the low-speed line support section of the other party's TDM counted a certain number of CD offs. For this reason, when the other party's TDM modem is connected, the RS off time is longer, and when the terminal device is connected, the CD off time is longer, and no consideration has been given to response, and on frequently used lines,
There was a problem that usage efficiency deteriorated.

It is an object of the present invention to eliminate the problems of the prior art, and the above object is to take a CD into a buffer at the same RT timing as the RD is taken into the buffer at the R, T timing,
This is achieved by transmitting the RD and CD to the other party's TDM while maintaining the time relationship between the RD and CD from the low-speed line.

[Operation] The circuit that takes in RD and CD6 into the buffer takes them in at the same timing FLT, so it operates to store FLD and CD at the same time. As a result, the relationship between RD and CD is
Since the data can be transmitted to the other party's TDM while being kept the same as when it came from a low-speed line, the CD-off information may become early and destroy the data, or the CD-off information may become slow and affect the response. Never.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

I will explain.

FIG. 1 shows an example of a system configuration in which the present invention is utilized, in which a terminal side modem M1. M2. M3 is a multipoint connection.

FIG. 2 is an internal configuration diagram of the low-speed line support section LAD9 of FIG. 1.

5 and 4 are internal configuration diagrams of the low-speed line support units I and AD1.

Figure 5 shows CD on/off and R from modem M1 in Figure 1.
D is the CD of the low-speed line support section LAD1 of the other party TDM1,
This is a time chart until it becomes RD.

When the low-speed line support unit LAD9 of the TDM2 takes in the RD from the low-speed line (Ml) shown in FIG. , same RT
Also import the CD at the same time. After this, OR circuit 14
The logical interest rate of the CDI and CD taken out from the FIFO is calculated and output as HCD. The input CD of this OR circuit 14 is earlier than the ON information of CD = iR,D.
This is for sending to M1, and is made possible by the delay of RD by the FIFO buffer 13. Also, FIFO buffer 1
The CDI traced to 3 has CD off information as the other party's TDM1.
accurately and to prevent unnecessary delays.

HRD and HCD are combined by SEI and circuit 22 as shown in the high-speed frame of FIG. This synthesized signal iI, AD
As high-speed frame data of 9, the multiplex control unit T D
The multiplex control unit TDM2 performs 7-raming on each line to create the high-speed frame shown in Figure 5, and I) SUl
Send to.

When creating the high-speed frame shown in Fig. 5, use the OR shown in Fig. 2.

By the circuit 14, the ON information of the CD is changed to a valid RD (D4
, D5. D6), transmission is possible without delay. Also, the CD off information is the last RD of the previous frame (
By transmitting the CD (C7) at the time of D7), the RD
Transmission to the other party's TDM 1 is possible while maintaining the relationship between the data and the CD.

In contrast, the low-speed line support section LAD1 of the other party TDM1
Now, extract only the data for your own line in the high-speed frame shown in Fig. 5 using the circuit shown in Fig. 3 or 4,
It is broken down into CD and RD as shown in Figure 5 and sent to CCP. Here, the case of FIG. 3 is an example in which a shift register with FF circuits 15 and 16 is used to guarantee data until CD-OFF, and FIG. 4 is an example in which a FIFO is used. The HCD of the OR circuit 17 in FIG. 3 and the OR circuit 21 in FIG. Send it to a low-speed line as a CD.

The difference between Fig. 3 and Fig. 4 is that the timing of sampling the CD is different.As shown in Fig. 5, Fig. 6 is the timing to take in the CD, RT2, and Fig. 4 is the timing to take in 0 and RD. CD information is sampled at RT1. Therefore, with the circuit shown in Figure 2, CD
If the off information is sent later than the data,
As shown in Figure 5, there is less time delay when importing by RT2 ('CD signal can be turned off. However, the time delay is equivalent to 1 bit time of high-speed data, and the speed of low-speed line is When it is slow and does not affect the response, the fourth
The circuit shown in the figure is small and effective.

As described above, according to this embodiment, it is possible to transmit a CD without the CD off information overtaking the data and without significant delay.

〔Effect of the invention〕

According to the present invention, the simultaneity of the received data of the modem interface and the carrier detection signal is maintained, the exclusive time of a certain line is shortened by turning on and off the carrier detection signal, and the efficiency of traffic is improved by improving the response. be.

[Brief explanation of the drawing]

FIG. 1 shows system configuration diagrams 1 and 2 of an embodiment of the present invention.
1 to 4 are block diagrams of the low-speed line support section, and FIG. 5 is a time chart showing the relationship between CD and RD. 1... Communication control device (CCP) 2.7... Low speed line support unit (1/AI) 1-16) 3
．． 6... Multiplex control unit (TDMl, 2) 4.5... Line termination unit (DSU'+, 2) 8^10... Modem (
M1S5) 11, 12...Terminal device (T1.2) 13, 18.1
9...Buffer 14, 17.21...OR circuit (OR) 1.

Claims (1)

[Claims] 1. In a time-division multiplexing and distribution device, when transmitting the carrier detection signal of the modem interface signal of the low-speed line of the multiplexing and distribution device between multiplexing and distribution devices, the received data of the modem interface signal is buffered at the reception timing. a circuit that simultaneously buffers the carrier detection signal of the modem interface signal along with the received data; a circuit that transmits information on whether the carrier detection signal is off or on after buffering to the other party's multiplexing/distributing device through a high-speed line; By having a circuit that transmits signal off or on information through a high-speed line and turns off or on the transmission request signal when the modem is connected to the corresponding low-speed line modem interface signal and the carrier detection signal when the terminal device is connected, A multiplexing and distributing device characterized by reducing the time lag of a carrier detection signal with respect to received data and shortening the time that a specific line is exclusively occupied.