Abstract: A method and apparatus for telephone call answer supervision, capable of detecting the completion of both national and international calls, which employ different answer confirmation formats, and provide confirmation that a placed call has been answered if least one of the following conditions occurs: 1) a tone of a given frequency, transmitted on the transmit line of a telephone, is detected as received back on the receive line; and 2) audio activity having a non-repetitive cadence is detected on both the transmit and receive lines of the telephone. Also provided is an autonomous pay telephone, such as a mobile telephone, which includes an arrangement for determining and accessing a call rate, per unit of time, for a call placed to a given telephone number, a display for displaying, in real-time as the call progresses, charges for a completed call as well as an accounting arrangement for storing charges accessed for each completed call.