| 摘要 |
PURPOSE:To display the available remaining time for telephone call without exerting any undesired influence on the telephone call, by sending charging information to a public telephone set over a subscriber-line signal channel in the form of an encoded digital signal. CONSTITUTION:When a user throws a coin into the coil storage part 15 of a public telephone set 1 and turns a dial 20, a station device 3 performs connection operation and also sends digital charging information to the telephone set 1 at prescribed intervals of time over a subscriber-line signal channel. The CPU28 of the telephone set 1, on the other hand, compares telephone call charge A, the sum of unit charge B, and the amount X0 of coins in a coin corridor; when X0-A>B, the remaining time when the telephone call can be continued is estimated and displayed on a display part 18, and the storage part 15 is driven to store coils in a coin box corresponding to the charge A. Simultaneously, the CPU28 sets a timer 26. Then, the CPU28 updates the display on the display part 18 at intervals of one second, and every time a unit time passes, some of coins in the coin corridor which correspond to the charge B are stored in the coin box. |
