JPS63181541A - Communication control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication control device having an interface circuit that can be directly connected to a high-speed digital line.

[Conventional technology]

The communication control equipment that connects to NTT's high-speed digital line is
It has the function of extracting the clock superimposed on the received data line from the digital line termination unit (DSU) installed by NTT, and sending data to the transmitting data line in synchronization with the clock. This type of communication control device operates on the clock from the digital line termination device [(1) 8U), so communication cannot be performed unless it is connected to the digital line termination device, and one communication control device can only operate on its own. I can't confirm.

Related devices of this type include, for example, Japanese Patent Laid-Open No. 60-74750.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration the operation means when the digital line termination unit (DSU) is not connected, and communication is performed without connecting the digital line termination unit.

There is a problem in that it is not possible to test data transmission and reception on a single communication control device, such as a loopback test, and there is also a problem in that it is not possible to perform data transmission and reception by directly connecting two communication control devices with a cable without going through a digital line termination device. there were.

An object of the present invention is to enable transmission/reception tests and data transmission/reception by directly connecting two communication control devices with a cable even when a digital line termination device is not connected.

[C] A precautionary measure to solve the problem] The above purpose is to provide an internal clock generation circuit and a clock switching circuit in the high-speed digital interface circuit of the communication control device, and to supply the clock to the transmitting and receiving circuit by an externally controlled signal. This is achieved by switching to select either the clock extracted from the line or the clock generated by the clock generation circuit.

[Effect]

When connecting a high-speed digital line to an external transmission/reception terminal using an externally controlled signal, select the clock extracted from the line, and select the clock generated by the internal clock generation circuit when returning the external transmission terminal to the external reception terminal. can.

Also, when connecting two communication control devices directly with a cable,
One communication control device selects the clock generated by the internal clock generation circuit, the other communication control device selects the clock extracted from the line, and communicates by connecting the external transmission terminal and external reception terminal to each other. Check the operation of the control device.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Fig. 2 is a connection diagram of a communication control device connected via a high-speed digital line, Fig. 1 is a configuration diagram of a communication control device according to the present invention, Fig. 3 is a connection diagram for explaining the loopback function, and Fig. 4 is a connection diagram for explaining direct connection to a communication control device.

In Fig. 2, 1 is a communication control device, 2 is a cable, and 3 is a communication control device.
is a digital terminal device, and 4 is a high-speed digital communication network.

As shown in FIG. 2, two communication control devices 1 are connected by a high-speed digital communication network 4, each with a digital terminal device 3.
The communication control device 1 extracts the clock weighted on the received data line from the data line.

Data reception and data transmission are performed using the extracted clock.

In FIG. 1, 5 is a high-speed digital interface circuit according to the present invention, and 6 is a clock extraction circuit.

7 is a clock generation circuit, and 8 is a clock switching circuit.

9 is a data receiving circuit, 10 is a data transmitting circuit, 11~
14 is a cable connection terminal for the high-speed digital interface circuit 50, 11 is a data reception terminal, and 12 is a clock switching control terminal; in this example, the clock switching control terminal 1
When ground is supplied to 2, the clock is generated by the clock generation circuit 7.
The operation will be explained using FIG.

If the communication control device 1 as shown in FIG. The clock extraction circuit 6 extracts a clock from the data line from the data line, and supplies the extracted clock via the data reception circuit 9 and the data transmission circuit 101C through the clock switching circuit 8.The data reception circuit 9 and the data transmission circuit 10 supply the Data is taken in from the reception terminal 11 and transmitted data is sent to the transmission terminal 13 using the clock.

In FIG. 3, 15 is a folding connector. The folding connector 15 connects the receiving terminal 11 and the transmitting terminal 13, and also connects the ground supply terminal 14 and the clock switching terminal 1.
By connecting this folding connector 15 to the output terminal of the high-speed digital interface circuit 5 of the communication control device 1, the clock of the clock generation circuit 7 is supplied to the data reception circuit 9 and the data transmission circuit 10. Therefore, the data sent from the data transmitting circuit 10 is received by the data receiving circuit 9 via the return connector 15, and by comparing the transmitted and received data, it is possible to confirm the operation of the high-speed digital interface circuit 5.

In FIG. 4, reference numeral 16 denotes a cable that directly connects the two communication control devices 1, with the data transmission terminal 16 connected to the reception terminal 11 of the other side, and the ground terminal 14 connected to the clock switching terminal 12 on one side. By adopting the connection configuration shown in FIG. 6, the communication control device 1 on one side operates with the clock of the clock generation circuit 7, and the communication control device 1 on the other side operates with the clock extracted from the received data line. To enable data transmission and reception between two communication control devices 1 even without a digital terminal device 6.

As described above, according to this embodiment, in a communication control device having a high-speed digital interface circuit, by using a return connector, it is possible to easily perform return operations for data transmission and reception.

Further, by using a direct connection cable, there is an effect that data can be transmitted and received between two communication control devices without using a digital terminal device.

〔Effect of the invention〕

According to the present invention, since it is possible to select either a clock extracted from a line by an external control signal or a clock generated internally by the communication control device itself, the communication control device can be operated without a digital line termination device being connected. Not only can loopback tests be performed, but data can also be sent and received by directly connecting two communication control devices with a cable.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a communication control device according to the present invention. FIG. 2 is a connection diagram of communication control devices connected via a high-speed digital line, FIG. 3 is a loopback connection diagram, and FIG. 4 is a direct connection diagram of two communication control devices. 6... Clock switching circuit 7... Clock generation circuit 8... Clock switching circuit 9... Data receiving circuit 10... Data transmitting circuit

Claims (1)

[Claims] 1. A communication control device having an external transmitting terminal connectable to a high-speed digital line and an external receiving terminal and a transmitting/receiving circuit is provided with a clock generation circuit and a clock switching circuit, and a clock is supplied to the transmitting/receiving circuit by an externally controlled signal. A communication control device characterized in that the communication control device switches to select either a clock extracted from the line or a clock generated by the clock generation circuit.