| 摘要 |
PURPOSE:To eliminate ineffective restriction of the extension of main wire request to simplify the operation of the attendant board operator, by providing a key for extension calling in the attendant board in PBX. CONSTITUTION:When extension EXT calls the operator of attendant board ATT and the operator responds to it, EXT requests main wire originating and hooks on. At this time, the earth is generated on the C line due to the contact of the K relay to hold network NW(1). The operator calls the main wire through NW(2) and depresses instantaneously key RING for extension calling provided in ATT to operate the R relay and transmits call signal IR to EXT. By off-hook of EXT, the RT relay is operated, and the R relay is released, and service between EXT and the operator becomes possible, and further, EXT and the main wire become the service state. |
