JPS61208989A - CATV terminal equipment - Google Patents

Abstract

PURPOSE:To discriminate whether a fault is in a network or in an terminal equipment by transmitting information data with the addition of check code data, and disconnecting the terminal equipment from the network at the terminal equipment when reception error exceeds a set value to conduct a test of the own circuit. CONSTITUTION:In the mutual information exchange between a center and the terminal equipments, transmission is performed with the addition of prescribed check code data in order to preserve data. The data at the terminal 2 transmitted from the center are fetched through a demodulator 5 to a microprocessor 6 after the polling signals are separated by a distributor 3, so that the number of error occurrence is held in a memory device 8. When the number of error occurrence exceeds a setting value, the processor 6 actuates a circuit switching device 4 to disconnect the cable network and the terminal equipments. A modulator 7 is used to conduct the test of the own circuit and stores the number of times of the error occurrence. From these results, whether the reception error fault due to network error or the reception fault error due to abnormalities in the terminal equipments can be discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an improvement of a terminal device for simplifying inspection and maintenance work in a CATV system.

(Prior art and its problems) Conventionally, in a CATV system, information exchange between the center and terminal devices is done by polling from the center to receive request data for receiving paid broadcasting, request data for information retrieval, etc. The center collects the information and provides the requested information to the center. In order to maintain and maintain these system functions, maintenance and inspection work must be performed periodically.

As the number of subscriber terminals increases with the development of CATV systems, in order to maintain the system, it is necessary for personnel with specialized knowledge to periodically check the functions. This increases the amount of work required to operate the system. Furthermore, when information exchange becomes defective, it is difficult to determine whether the cause is the line or a failure of the equipment.

(Purpose) In order to eliminate these drawbacks, the present invention adds specified check code data to normal information exchange data and transmits the data, and when a receiving error occurs, the receiving terminal device stores the number of times it has occurred and stores it in advance. When the set number of occurrences is exceeded, the terminal device is disconnected from the line and its own transmitted data is directly fetched into the receiving section, and a loop test is performed to determine whether the problem is due to a line failure or a failure in the terminal device's transmitting and receiving circuits. The purpose of this is to simplify maintenance work.

(Embodiment) A two-way CATV system requires highly reliable equipment to maintain its functionality. However, in actual systems, the quality of the cable network tends to deteriorate, the characteristics of the transmitting and receiving circuits change over time, and the level tends to deteriorate. For this reason, when information exchange becomes defective, it takes a great deal of time to investigate the cause. The present invention includes these,
This is intended to simplify maintenance work.

The figure shows an embodiment of the invention. When information is exchanged between the center and the terminal device, prescribed check code data is added to the data in order to protect the data. Data transmitted from the center via the cable line network No. 2 is separated into polling signals, CATV video and audio signals by the distributor No. 3.

The polling signal transmitted from the center is digitally encoded by demodulator 5 and taken into microprocessor 6. The microprocessor determines whether the received data is normal data or not, and if it is determined to be an error, this number of times is held in the storage device 8.

When the number of error occurrences exceeds the set number, the microprocessor activates the 40 line switch through the 13 line switch activation signal lines to disconnect the cable network and the terminal equipment. Thereafter, the self-transmission and reception circuits are tested by directly connecting predetermined check and code data from the microprocessor from the transmitting section consisting of the modulator 7 to the demodulator receiving section 5.

If an error occurs as a result, it is held in the storage device 8. During maintenance work, 11 printers are connected externally and a print command is issued to print out the contents held in 8 storage devices to determine whether there is a 9 line failure or a terminal device failure.

In addition, when recovering from a failure, upon request from the center, the data stored in the error occurrence is sent from the terminal device, and the data is managed collectively at the center, and materials such as monthly maintenance reports are saved by editing and printing the data. be able to.

(Effects) As described above, according to the present invention, it is possible to constantly monitor the error occurrence state and accurately determine whether the error is due to a 9 line failure or a CATV terminal equipment failure, thereby simplifying maintenance work.

[Brief explanation of the drawing]

The figure is a block diagram of an embodiment of the invention. 1: Transmission data example, 2: CATV cable network,
3: distributor, 4: line switch, 5: demodulator receiving section. 6: Microprocessor, 7: Modulator transmitter, 8: Storage device, 9: Printer output circuit, 10: Video.

Claims (1)

[Claims] In a two-way CATV system, a specified check code is transmitted as part of the normally transmitted data between the center and the terminal equipment during mutual information exchange polling, and on the receiving side, the received data is constantly monitored by a microprocessor to prevent reception errors. On the other hand, the receiving circuit receives transmission data from the transmitting circuit of the terminal device, tests its own circuit, and stores the number of errors that occur. Based on these results, it is determined whether the receiving error is due to a line abnormality or the terminal device A CATV terminal device characterized in that it determines whether a reception error failure is due to an abnormality.