Abstract: A method of adjusting the pulse rate of a local clock (1) by generating a first pulse train at a first predetermined rate, dividing the pulse train by a divisor (3) to produce a second pulse train. The value of the divisor (3) is selected (4,5,6) so that the rate of the second pulse train is adjusted within a predetermined range.

Abstract: A system for monitoring use of a utility at a consumer's premises is disclosed. The system may include monitoring apparatus to detect use of the utility, a first register to store an indicator signal indicating whether or not use of the utility at the consumer's premises is authorized, and an unauthorized use signal generator, responsive to the monitoring apparatus output and the contents of the register, to generate an unauthorized use signal when the monitoring apparatus output indicates use of the utility and the first register contains an indicator signal indicating that use is not authorized.

Abstract: DC offset is measured by separating the positive and negative half cycles of the AC waveform, obtaining a measure of the energy content of each type of half cycle and subtracting one from the other and accumulating the result. The accumulated result is measured against a threshold which is selected to have a known relationship to the units used to measure the DC offset. Each time the threshold is exceeded, this increments a counter and at the same time resets the accumulator. The contents of the counter can then be multiplied by an appropriate scaling factor. The square root of this result gives a measure of DC offset.

Abstract: An interface arrangement (2) comprising interface circuits (5,7) and processor (14) allows a personal computer (10) to operate in conjunction with a telephone subset (1) associated with a main switch system (9) in which the signalling systems used by the telephone subset and the computer differ. The interface arrangement allows the subset and the computer to be connected to the subsets switching system to permit at least some of the subsets signalling functions to be performed by the computer.

Abstract: A telemetry terminal for controlling and metering consumption of electricity, water, etc., at a consumer's premises having a programmable processor. The programmable processor includes a receiver to receive instructions over the phone line to operate switching controls and a transmitter to transmit readings stored in the processor from meters to a central control station over the phone line. The processor also has a switching control routine in the event of an interruption to the phone line.