| 摘要 |
PURPOSE:To make a user supplement charge with the margin of time even when the cycle of an accounting signal is short, by calculating the incoming cycle of the accounting signal, and extracting a remaining frequency for starting request which is preliminary fixed with the margin of time. CONSTITUTION:If a user deposit a coin, its signal is supplied to a controlling circuit 1 via a signal terminal 7. The circuit 1 calculates a remaining frequency from the amount of the deposited coin by using preliminary fixed unit rate for conversation and stores the data in a memory 4a. When the state of conversation starts, an accounting signal is inputted to a timer 3 via a speaking circuit 5 and also to the circuit 1, and the circuit 1 substracts the content of the memory 4a. When the next accounting signal comes in, the timer 3 transmits a signal corresponding to the cycle of the accounting signal to the circuit 1. The circuit 1 extracts a data indicating a request indication starting frequency out of a memory 4b and compares it with the content of the memory 4(a). If the content of the memory 4a becomes less than the content of the memory 4b, the circuit 1 actuates a display 2 to flash. As a result, the user is requested to add a coin. |
