Electronic equipment for acoustic room monitoring - uses programmable circuitry powered by two wire supply in conjunction with telephone system

摘要

The system consists of a switching network (1), a programmable control unit (2) with a microprocessor (3), resistors (4,....9) and switches (10, 11, 12) connected to a two wire supply (U1, U2) and various telephones (A, B etc.), and further apparatus (C) for acoustic monitoring. Preferably, a microspheres is used in conjunction with threshold circuits to generate busy signals which are received at the control unit (2). This circuitry is powered from the telephones circuit. A signal is then switched through to one of the telephones (A, B). USE/ADVANTAGE - Room monitoring for children. Programmable system.