| 摘要 |
PURPOSE:To hold the outgoing trunk receiving the control signal to busy state, by easily detecting called party restoring state caused after the caller advance call state with the relay trunk between stations and the state of caller recall from the called party. CONSTITUTION:The exchanger in which the restoration control system of relay line trunk between stations is called party control system and the ground state of the terminals A2, B2 of the incoming trunk of called station is taken as caller recall information at the detected time, is provided. Further, after the response of called party, the relay R operated when the relay E is restored is provided in parallel with the loop system response monitor circuit connected between the terminals A1 and B1 opposing to the incoming trunk of the called station of the outgoing trunk of calling station side, and this relay R is operated when current flows from the terminal B1 to A1. With the combination of the relays R, A and E for the operation and restoration state and collation with caller state called party ON-hook at caller ON-hook or the state of recall of caller can distinctedly be detected. |
