a method and apparatus which permits a power utility to have direct control of customers loads with a view toward facilitating enablement of a load management philosophy which includes peak shaving and load deferral . a master control station , which comprises a programmable microprocessor - based central controller , is in two - way communication with a plurality of substation injection units , one of each of which is positioned at a separate substation of the power utility . each substation injection unit , under the control of its own microprocessor , responds to master control signals from the master control station to inject a pulse code signal onto the power lines of the utility . the system includes a plurality of remote receiver units which are positioned at and connected to control the on and off times of customer loads . each remote receiver unit is preset to respond to particular pulse code signals from the substation injection units to carry out the desired command functions , which can be implemented either automatically or manually on a fixed or dynamic - cycle basis as the need arises . the system utilizes a command signal and pulse code signal verification technique to insure system integrity and reliability .