| 摘要 |
PURPOSE:To eliminate compentition of channels, by limiting the interruption of an outsider to a call channel at the calling subscriber's will. CONSTITUTION:An ATIS code or an interruption-enable-/unable-code is transmitted every second minute during a busy mode. Then the interruption-enable-/ unable-code is discriminated by a code detector 6 by continuing reception for a minute after a system of an outsider desiring an interruption sets a channel to the busy channel. A monitor state is automatically obtained when an interruption inhibition code is detected. (It is supposed that a code of ''1'', for example, is set to an interruption bit and transmitted from a code generator 10 after a calling subscriber under a busy state operates a switch 21 to give an inhibition command.) Thus a forcible interruption is inhibited. While an automatic changeover is carried out to a call state to enable an interrupted call after an interruption-enable-code (suc as ''0'') is detected. In such a way, it is possible to control the forcible interruption of an outsider at the calling subscriber's will. This system eliminates unnecessary competition of channels. |
