JPS61137434A - Control circuit for test of transmission line - Google Patents

Abstract

PURPOSE:To test a transmission line only with a line for signal transmission without sending out a signal to the line all the time for maintaining a test state by providing a control circuit which allows signals to by-pass a signal regenerating circuit in a repeater. CONSTITUTION:A test start signal from a station is passed through a down circuit 10 and detected by a test start signal detecting circuit 1 to control the control circuit 2, thereby setting a switch 4, which is set at the side of the signal regenerating circuit 3 in the repeater to the side of a detour line 5. Consequently, the transmission line is considered as a couple of cables. A test end signal from the station is detected by a test end signal detecting circuit 6 to control a test end signal sending-back control circuit 7, thereby setting a switch 8 so that the test end signal is sent out to the side of an up circuit 11. A host repeater detects the test end signal from the low rank repeater by a test end signal detecting circuit 9 and the control circuit 2 is so controlled as to maintain the test state when the test end signal is detected or to control the switch 4 so that the test state is reset unless the test end signal is detected. The test state is thus reset successively from low rank repeaters.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transmission line testing method, and particularly to a transmission line testing method for a transmission line having a repeater.

Conventional technology When testing a transmission line with a repeater, it is necessary to bypass the signal regeneration circuit in the repeater and set the transmission line so that it can be regarded as a pair of cables. This setting method provides a control line for setting test conditions separately from the shield transmission line.

There are methods for setting by sending a control signal onto this line, and methods for setting by superimposing a DC signal on the transmission line and operating a relay in a repeater.

The problem that the invention aims to solve However, with this conventional setting method.

There are disadvantages such as the need to provide an extra line in addition to the signal transmission line, or the need to constantly send signals to the line to maintain the test state settings, and the test items are limited.

The present invention has been made in view of the above-mentioned conventional circumstances.
Therefore, an object of the present invention is to solve the above-mentioned drawbacks by providing a control circuit in the repeater to bypass the signal regeneration circuit, and to use only a filter transmission line without providing a control line for setting test conditions. Another object of the present invention is to provide a new transmission line test control circuit that can perform line tests on transmission lines with repeaters without the need to constantly send signals to the line to maintain test state settings. .

Means for Solving the Problems In order to achieve the above object, a transmission line test control circuit according to the present invention is applied to a transmission line having a repeater.

A test start signal detection circuit connected to the downlink side from the station in the repeater, and a control circuit and switch for bypassing the signal regeneration circuit in the repeater.

Furthermore, a test start signal detection circuit connected to the detour line side,
As a result, the test terminal is configured to include a control circuit and a switch for setting the signal to be sent back to the station.

EMBODIMENT OF THE INVENTION Next, the present invention will be described in detail with reference to FIG. 1 for a preferred embodiment thereof.

FIG. 1 is a block diagram showing an example of the winding of the present invention. In Figure 1, the test start signal from the °C1 station is detected by the test start signal detection circuit 1 through the downlink 10 from the station, controls the control circuit 2, and is set on the signal regeneration circuit 3 side in the repeater. Detour line 5 @
Set to . Through this control, the transmission path is set in a state where it can be regarded as a pair of cables.

The test state is canceled by sending a test completion signal from the station. The test end 1 word from the station is emitted by the test start signal detection circuit 6, which controls the test end signal return control circuit 7 and switches the switch 8 so as to send the test end signal to the uplink 11 side to the 1st station. Set. As a result, the higher-ranking repeater receives the test end signal from the lower order, and the lowest-ranking repeater does not receive the test end signal from the uplink 11 to the station. This test end signal from the lower level is detected by the test start signal detection circuit 9.

When test end No. 1 is detected, the control circuit 2 is controlled to maintain the test state, and when the test end signal is not detected, the switch 4 is set so as to release the test state. In this way, the test state is released from the lower repeaters in order.

Effects of the Invention As described above, 1. With the transmission line test control circuit according to the present invention, line tests of transmission lines can be carried out using only the signal transmission line and without constantly sending signals to the line in order to maintain the test state. be able to.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one practical example of the present invention. 1...Test start signal detection circuit, 2・φ・control circuit, 3
・Signal regeneration circuit, 4...Switch, 5...Detour line, 6.Test start signal detection circuit, 7.φ test end signal return control circuit, 8.Switch, 9...・Test start signal detection circuit. 10・Fist・down line from station, 11...uplink to 0 station

Claims (1)

[Claims] In a transmission line having a repeater, a test start signal detection circuit connected to the downlink side from the station in the repeater, a control circuit that causes the test start signal detection circuit to bypass the signal regeneration circuit in the repeater, and It is characterized by comprising a switch, a test end signal detection circuit further connected to the detour line side, and a control circuit and a switch configured to send the test end signal back to the bow side by the test end signal detection circuit. Transmission line test control circuit.