| 摘要 |
<p>PURPOSE:To make small the circuit by the subscriber lines electronized and circuit- integrated, by constituting the electronic contact switch network such as time sharing switch network as the subscriber lines which can be connected to any of the dial type telephone sets and push button dial type telephone sets. CONSTITUTION:The transmission and reception of the high amplitude signal such as communication current, callout signal and howler signal required for the subscriber telephone set TEL is made at the subscriber circuit SC provided at the subscriber lines LINE of the electronic contact switch network TDNW. Further, the relay line interface trunk TRKB handles the transmission and reception of signal with the opposing exchanger and the in-band signal transmission and reception trunk TRKC handles the transmission and reception of the low amplitude signal such as call-out tone, busy tone, dial tone and push button dial signal. The subscriber circuit SC consists of the switches SW0-SW9 by semiconductors, overvoltage and overcurrent protection circuit ARR, ring trip circuit TRP, DC power supplies E0, E1, communication current supply circuits CS0, CS1, and subscriber monitor circuit DET for circuit integration.</p> |
