| 摘要 |
PURPOSE:To display a calling subscriber class, by transmitting a call signal of a polarity opposite to that of a normal call signal at the incoming time from a specific extension. CONSTITUTION:In case of calling from a specific extension, marker M operates specific extension class receiving relay MJ of idle extension mutual trunk IOT on a basis of information from the originating register when IOT is selected. Thus, contact mj<1> is switched, and the DC power source of the call signal is switched from -EV to +EBV, and therefore, the signal polarity is inverted. Since neon lamp NL is lit by this inverted signal, it is displayed that the call comes from the specific extension. |
