[54] DIGITAL RELAY SYSTEMS
[75] Inventors: John A. Adderley, Holm Rook;
Dennis R. Bester, Coventry, both of
England
[73] Assignee: The General Electric Company
Limited, London, England
[21] Appl. No.: 950,514
[22] Filed: Oct. 11,1978
[51] Int. CU H04K 1/00
[52] U.S. CI 375/38; 455/8;
340/147 SC; 371/8
[58] Field of Search 325/2, 3.56, 304, 305;
340/146.1 BE, 147 SC
[56] References Cited
U.S. PATENT DOCUMENTS
3,072,748 1/1963 Abraham 325/2
3,681,694 8/1972 Sarati 325/3
4,052,670 10/1977 Watanabe et al 325/56
Primary Examiner—Benedict V. Safourek
Attorney, Agent, or Firm—Kirschstein, Kirschstein,
Ottinger & Cobrin
[57] ABSTRACT
In a digital relay system, a standby channel is arranged to replace any one of five main channels. The standby channel contains a variable delay, and the data from the main channel to be replaced is passed along the standby channel prior to the changeover and is brought into synchronism with the data in the respective main channel by automatically controlling the length of the delay introduced by the variable delay arrangement, so that there is no slip or break in the data of the switched channel.
6 Claims, 5 Drawing Figures
