| 摘要 |
PURPOSE:To switch and connect a low-speed signal and a high-speed signal transparently as they are, by separating the low-speed signal and the high-speed signal from each other in a subscriber interface circuit connecting the latter directly to a main channel network and multiplexing the former with low-speed signals from other terminals and demultiplexing them to connect the latter to the main channel network. CONSTITUTION:In case of intra-office connection, the high-speed signal from a subscriber's terminal 100 is transmitted to a terminal 10n through a high-speed signal ihterface IF circuit 211, etc. The low-speed signal is transmitted to a time-division multiplexing circuit 40 for low-speed signal and is multiplexed with other low-speed signals and is transmitted to a main channel network 300. The turned-back signal is demultiplexed by a time-division multiplexing circuit 500 for low-speed signal and a subswitch 400 for low-speed signal. In case of the transmission from the terminal 100 to a terminal 10m in the inter-office connection, low-speed and high-speed data are transmitted to the network 300 through said course and are multiplexed with other high-speed signals by a trunk IF circuit 600 and is demultiplexed again to high-speed signal groups by an IF601 and is transmitted to a network 301. The high-speed signal is demultiplexed to the low-speed signal by a time-division multiplexing circuit 501 for low-speed signal and a subswitch 401 for low-speed signal and is transmitted to the terminal 10m. The high-speed signal is transmitted directly to an IF circuit 21m.
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