PURPOSE: To realize the O/1 system switching method without short break which compares phases of user cell numbers to always match the phases of user cells in the ATM communication system of the SDH base.
CONSTITUTION: A user cell number from a user cell number adding part 9 is added to the first user cell by transmission format conversion parts 7 and 8 on the transmission side. The first user cell number is extracted by a phase deviation detecting part 2 on the reception side, and numbers of respective user cells are reproduced to detect the phase system between both systems. This phase difference detection signal is sent to system 0 and system 1 reception format conversion parts 3 and 4, and the ATM output signal on the leading phase side is delayed to match the phases of both systems. A SEL part 1 receives ATM signals, whose phases are matched, to perform switching without short break.
UEDA HIROMI
OTA HIROSHI
NIPPON TELEGRAPH & TELEPHONE
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