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( 7797 of 7797 ) |
United States Patent | 3,569,635 |
Bloch , et al. | March 9, 1971 |
A telecommunications system includes a master station which is in communication with any one of a number of outstations via one or the other leg of the two legs of a closed loop cable linking all the outstations along the cable route. A pilot tone is transmitted around the loop (which may be a four-wire telephone circuit) to indicate the occurrence of a fault and simultaneously to initiate switching operations to switch outstations beyond the fault to a healthy leg and isolate the faulty section of the line.
Inventors: | Bloch; Cyril Ettienne (London, EN), Teacher; Victor (Enfield, EN) |
Assignee: |
International Standard Electric Corporation
( |
Appl. No.: | 04/674,304 |
Filed: | October 10, 1967 |
Oct 28, 1966 [GB] | 48370 | |||
Current U.S. Class: | 370/222 ; 178/2D; 340/2.7 |
Current International Class: | H04Q 5/00 (20060101); H04Q 5/02 (20060101); H04q 009/02 () |
Field of Search: | 179/2,18.21,18 (FW)/ 179/16.09 |
2224374 | December 1940 | Baughman |
3335227 | August 1967 | Jackel |
3409877 | November 1968 | Alterman et al. |
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