Programmable traffic-measuring unit for telecommunication system

Abstract

A programmable unit for the recordal of traffic measurements in a telecommunication system comprises a processor which, in accordance with a stored program, cyclically scans a multiplicity of voltage sensors that are connected to incoming wires from respective signal sources such as wires of subscriber lines terminating at a central office or exchange. The sensors step down the incoming signal levels to a voltage range compatible with the operation of logical circuitry and are connected in sets of eight to respective inputs of a multiplexer whose eight-lead output multiple extends to a comparator receiving a variable threshold voltage from the processor via a digital/analog converter. The magnitude of this threshold voltage is individually determined by the program for each time slot in which a set of eight sensors is connected to the comparator; the latter delivers to the processor an eight-bit word or byte indicating the instant state of activity of the corresponding signal sources. These sources could also be constituted by the outputs of a frequency digitizer to which multifrequency-coded selection signals, dial tones, ringing frequencies and busy signals may be transmitted from the associated subscriber lines. The measuring unit could further be used to check on the operation of traffic-monitoring equipment using cascaded relays. The data supplied by the threshold comparator to the processor are recorded on a magnetic tape and/or a printer; a supplemental unit may include additional tape recorders designed to bridge the gap between cassette changes of the main recorder.