Call cost calculator for telephone system - determines distance between exchanges from geographic coordinates

摘要

The call cost calculator, for telephone calls, determines the criteria (tariff zone, tariff rate) affecting the cost of a call between two exchanges. A system of translators produces coordinates (x, y) defining the locations of all exchanges. These coordinates are produced in response to the area code dialled. - The coordinates of the calling exchange are subtracted from those of the called exchange to determine the distance between the two. The tariff zone rate applicable to this distance is then used to calculate the rate for the call.