Electronic temperature control system

A control system for a plurality of temperature controlling devices, each of which is disposed in a structure and is connected to an existing electrical power distribution network and each including a control circuit responsive to temperature conditions at a location in said structure to connect the device to the electrical conductor network for energization, comprising:

• a control transmitter responsive to each of a plurality of combinations of temperature and the passage of preselected periods of time to impose electrical pulses of different predetermined control frequencies on said conductor network at a pulse rate corresponding to the power supply frequency,
• said transmitter including:
• a plurality of fixed frequency oscillators each operable at a frequency greater than the power supply frequency,
• first gating circuit means for permitting each of said oscillators to provide pulses at a rate corresponding to the power supply frequency,
• a time clock connected to each of said oscillators to prevent oscillation of the oscillator except at a time period determined by the time clock,
• a master thermostat for monitoring temperature within the structure, and
• a second gating circuit means for imposing said oscillator pulses on said conductor network responsive to the temperature monitored by the master thermostat;
• and,
• a receiver associated with each of said plurality of devices responding to the presence of pulses of a different one of said predetermined control frequencies to render the control circuit for the device inoperative.