| 摘要 |
<p>PURPOSE:To economize a calling system, by selecting types of signals calling respective multiparty telephone sets and by providing a trunk, which monitors off- hook of multiparty telephone sets, commonly to these many multiparty telephone set lines. CONSTITUTION:When the number of telephone set SUB.B is dialed, a closed circuit of the path of telephone set SUB.A-telephone set SUB.B-8-party trunk 8PT- main link switch SW-8-party trunk 8OST is formed by 8-party telephone set mutual connection and trunk selection means. When marker MKR selects trunk 8OST, call signal information corresponding to telephone set SUB.B is sent to trunk 8OST. Then, the call sounder of telephone set SUB.B sounds to call. When telephone set SUB.B hooks off the handset to respond, the response monitor circuit in trunk 8OST is operated to stop transmission of the call signal.</p> |
