| 摘要 |
PROBLEM TO BE SOLVED: To provide a transmission system for digital communication where a short transmission system switching time is enough on the occurrence of a fault in an active transmission system. SOLUTION: On the occurrence of a fault in an active transmission system 1, a transmission system changeover relay 3 of the transmission system for digital communication switches connection of a track circuit 4 from the active transmission system 1 to a standby transmission system 2. The changeover of the transmission system is detected by a contact 6 in interlocking with the transmission system changeover relay 3 and it informs the standby transmission system 2 about the changeover. Thus, the standby transmission system 2 once interrupts the transmission and then immediately re-transmits a frame having been sent when the transmission is interrupted after that from its start bit. Thus, the standby transmission system 2 can transmit the frame again without awaiting a re-transmission request from a receiver 5 and then the transmission system changeover time can be reduced.
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