| 摘要 |
PURPOSE:To count and display the message rate despite no detection of a reverse signal, by starting the counting of duration of call when a prescribed period elapses after the dial digits are detected. CONSTITUTION:A call given from a subscriber SUB is detected at a loop detecting part via a detecting circuit C, and then a dial digit detecting part DS is actuated. Then the dial is detected at the part DS and via the circuit C. A reverse detecting part RV is actuated after the final digit of the dial is detected, and a time counter TC is set. The counter TC actuates a call duration counting part T when 5 seconds, for example, have passed. If the reverse signal is detected before 5 seconds elapse, the counter TC is reset. At the same time, the part T is actuated. |
