Loop transmission system and method of controlling the loop-back condition thereof
US4542496A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 22, 1983 |
| Grant date | Sep 17, 1985 |
| Priority date | — |
| Expiry date | Aug 22, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/437
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A loop transmission system and a method of controlling the loop-back condition thereof. The loop transmission system comprises a plurality of node stations, a supervisory station, and two duplicate loop transmission lines which transmit signals in opposite directions. In the loop transmission system, the supervisory station first sends out loop-back commands via both of the duplicate loop transmission lines when faults are detected on both of the duplicate loop transmission lines at the same time. Each of the node stations establishes a loop-back path while retaining a connection path to a succeeding node station upon the receipt of a loop-back command. The loop-back path is released only in the node stations which receive signals normally from both of the duplicate loop transmission lines when the supervisory station sends release commands to the node stations after sending the loopback commands.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.