| 摘要 |
PURPOSE:To clarify mis-operation and incorrect operation by providing a contact of a blocking relay disabling the transmission in response to mis-operation of a charged call. CONSTITUTION:When an emergency switch ES is operated, the dial calling only is supervised and the emergency number is permitted for free from charge, and when it is judged to be an inhibited number, a cut-off relay RL is operated, a contact rl<1> inserts a resistor Rt into a loop circuit via a contact lp<1> during restoring to open a DC loop and restore the exchange. When the emergency switch ES only is not operated and the inhibiting number is transmitted by mis-operation, only a block relay TS is actuated, a make contact of the relay TS is closed for a transmitter T of a talking circuit TKC so as to disable talking. Causes to disabled talking are discriminated according to the states. |
