Abstract: A call control apparatus for a pay phone includes a reading unit, a calculating unit, and a call enable unit. The reading unit reads out value information of an inserted card. The calculating unit calculates a call time corresponding to a ratio of the value information to a unit call fee when the value information read out by the reading unit does not reach the unit call fee. The call enable unit allows a call service by the call time calculated by the calculating unit.

Abstract: A public telephone set includes a communication enabling unit, a signal detector, a timer, and a CPU. The communication enabling unit enables incoming communication upon formation of a DC loop based on an incoming call. The signal detector detects a protocol signal from a maintenance center or a service center via the office line. The timer is started upon formation of the DC loop. The CPU instructs to send out alarm information to the maintenance or the service center via the office line when the signal detector generates a detection output during an operation of the timer.