Patent ID: 7515527

Claim:
An SDH transmission apparatus including a low-speed part, a high-speed part, and a cross-connect part for multiplexing a signal of the low-speed part side into a signal of the high-speed part side, wherein: the low speed part includes a first signal transmission part and a second signal transmission part, each signal transmission part including an active transmission part and a standby transmission part; the SDH transmission apparatus is configured such that an active transmission part of the first signal transmission part transmits a signal to a first transmission line via the high-speed part, and an active transmission part of the second signal transmission part transmits a signal to a second transmission line via the high-speed part; the SDH transmission apparatus includes a transmission control part for causing a standby transmission part of the first signal transmission part to send a part of signals supplied to the first signal transmission part to the second transmission line via the high-speed part when a traffic amount of the signals supplied to the first signal transmission part exceed a predetermined value; and the transmission control part includes a part for receiving a signal output from the standby transmission part of the first signal transmission part and a signal output from the active transmission part of the second signal transmission part so as to select a normal signal from among the received signals and output the normal signal.