| 摘要 |
PURPOSE:To eliminate a troublesome urging signal in case of a limitless short distance communication, by counting the number of incomings of charging signal, discriminating if the call is the limitless short distance call, and controlling the transmission of the urging signal. CONSTITUTION:A B output of a counter 12 is ''O'' at initial state, and it becomes ''1'' with counts twice. Thus, when a charging signal incoming is once and the call is a limitless short distance call, the B output of the counter 12 is always at ''O''. When a remote call is present where the incoming is two or more times, the B output is stored as ''1''. In case of the limitless short distance call, the calling charge for one call's share is contained with the incoming of the charging signal, and even if the rsidual amount is less than the one call's share, since the B output is at ''O'', no urging signal is transmitted. |
