Method and apparatus for communicating control and other information over a power bus

A vehicular based system for providing controllable audible and/or visible warning indications that a law enforcement and/or rescue emergency exists, said system comprising:

• a current modulator;
• a battery coupled to said current modulator, said battery providing an output voltage that is at least in part responsive to said current modulator;
• and
• a voltage demodulator coupled to said battery, said voltage demodulator demodulating said battery output voltage and outputting responsive control signals, and
• a light display unit responsive to said control signals, said light display unit comprising a light and sound bar mounted to the exterior roof of said vehicle.

In a vehicle including a finite power source connected to a power bus, a method of using said power bus to communicate control signaling to a device mounted on said vehicle, said method comprising:

• means coupled to a power bus for using an information signal to modulate a current sink at least in part in response to a control signal, said modulated current sink inducing voltage fluctuations at said power source that are at least in part in response to said information signal;
• means coupled to said power bus for sensing said voltage fluctuations on said power bus;
• and
• means coupled to said sensing means for demodulating said sensed voltage fluctuations to recover said information signal.

A method of using a power source connected to a power bus to communicate information to a device coupled to said power bus, said method comprising:

• using an information signal to modulate a current sink coupled to said power source, said modulated current sink inducing voltage fluctuations at said power source that are in response to said information signal;
• sensing said voltage fluctuations on said power bus;
• and
• demodulating said sensed voltage fluctuations to recover said information signal.

A system for using a power source connected to a power line to communicate information to a device coupled to said power line, said system comprising:

• a data transmitter that induces fluctuations on said power line in response to said information signal;
• a data receiver coupled to said power line, said data receiver capturing said fluctuations on said power line and performing at least action in response thereto;
• and
• a load interrupter coupled to said data receiver, said load interrupter temporarily decouples at least one load from said power line during said capturing of fluctuations.

On a vehicle based system for providing controllable audible and/or visible warning indications that a law enforcement and/or rescue emergency exists, said system comprising:

• a data transmitter connected to said powerline, said data transmitter inserting a control signal onto said powerline;
• a data receiver connected to said powerline, said data receiver obtaining said control signal from said powerline;
• and
• a light bar control unit coupled to said data receiver, said light bar control unit controlling light and sound emanating from the exterior roof of said vehicle at least in part in response to said obtained control signal.

A light bar of the type for mounting on the exterior roof of a law enforcement and/or rescue vehicle, said light bar comprising:

• a power connector;
• at least one rotator;
• a data receiver coupled to said power connector, said data receiver receiving control signals from said power connector;
• and
• a controller that selectively applies power to said rotator at least in part in response to said received control signals, said controller momentarily interrupting power to said rotator during control signal reception by said data receiver.