Telephone system screening out unwanted signals - has switch-bank with settings for programming from subscriber and remote telephones

摘要

The telephone system has an accessory unit to screen out undesirable signals from desirable signals. It can also be used for remote control of the function of the various electrical controls. It consist of a switch which is used to programme the system from the telephone set of the subscriber using local energy and set in a particular position. The switch can be changed over to a different position where the system can be programmed from a different telephone set via ordinary telephone lines. There is also a triggering pushbutton and a decoding selector system. The signal transmiter and receiver is fitted with a signalling unit and a function generator in a normally closed circuit. The transmitter and a scanner will open the circuit to the signalling unit. The function generator will close the circuit.