| 摘要 |
PURPOSE:To display a remaining talking time by providing a function converting a talking charge into a talking time to a public telephone set. CONSTITUTION:When a talking charge is deposited to a public telephone set, a deposited momentary amount calculating circuit (a) and a unit charge calculation circuit (b) calculate the unit charge to the deposited talking charge. Then the total number of signals A outputted from the exchange is counted, a unit charge subtraction circuit (e) calculates the counted signal number to calculate the unit charge number corresponding to the remaining talking charge. The calculated unit charge is multiplied with the talking time for the unit charge's share to be measured and the result is displayed.
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