Autonomous subscriber telephone charge rate meter - uses microprocessor controlling memory with price data to command pulse generator whose output determines charge rate

摘要

The device includes a memory (M) in which information relevant to various calls is stored for call-up by the subscriber together with corresponding cost cycles. A microprocessor (MP) connected to the subscriber telephone line (L) and memory detects an operational state of the line and compares the call information stored in the memory with the call information signal, such as dadialled number, from the subscriber to produce an output determining the relevant cost cycle. Once a polarity inversion on the phone line, occurs indicating a connected call, the microprocessor output is applied to a pulse generator (GI) whose pulses are counted in the microprocessor to determine the call cost. Data concerning time and day can also be input to the microprocessor for calculating cheap rates. A reduction in the rate would then be implemented by filtering a number of counting pulses.