| 摘要 |
PURPOSE:To surely send a ringer signal to a slave set even when an incoming signal level is decreased by varying the period of the ringer signal sent to the slave set in response to the period of a detection signal from a ringer detection circuit detecting the incoming signal. CONSTITUTION:The system is provided with a ringer detection circuit 26 detecting a ringer signal from an external line by a master set and a control circuit 9 discriminating the period of the detection signal from the ringer detection circuit 20 and varying the period of the ringer signal sent to the slave set based on the result of discrimination. Then the period of the detection signal from the ringer detection circuit 26 is discriminated and when, e.g. the period is a period of H level for 1sec and L level for 2sec, the ringer signal is sent to the slave set by the period and when the period is 0.25sec, the ringer signal is sent to the slave set with the period set newly. Thus, even when the level of an incoming signal is decreased depending on the condition of the line, the ringer signal is sent surely to the slave set. |
