| 摘要 |
Key-phone circuit with meeting facility is composed of a closed loop circuit on DTMF circuit added to a hook switch, a hook/hold detection circuit and a local selection switching circuit connected in parallel to two communication power sources. Its facility provides two types of connection. One is a connection between one private subscriber line and two local subscriber lines; and the other is a connection between two private subscriber lines and one local subscriber line by a local selection switching circuit.
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