| 摘要 |
PURPOSE:To attain howling operation by releasing disable reception when a normal operation is not executed during a prescribed time after hook-off in a public telephone set of the advanced loop system to ring a receiver. CONSTITUTION:When no detected output of a coin detection circuit CCD is caused during a prescribed time after off-hook, no output of a dial circuit DIC is caused, and no normal operation for dialing is performed, then a control section CNT does not control the operation to a block relay SS, a switch SW is controlled to open a DC loop circuit. Since a loop current flowing to a release relay SH is given in response to the off-state of the switch SW, the disabled state of talking is released and a receiver is rung when a howler tone reaches. |
