Patent ID: 7286859

Claim:
A method of detecting the broadcasting of an RF message from a remote transmitter to an in-vehicle receiver, said RF message including an initial preamble having a plurality of pulses, said method comprising the steps of: providing power to said receiver for a first predetermined period of time; counting a number of preamble pulses received during said first predetermined period of time; and determining whether said number of preamble pulses received during said first predetermined period of time are between a first predetermined number of preamble pulses and a second predetermined number of preamble pulses; if said number of preamble pulses are greater than said first predetermined number of preamble pulses, then power is automatically provided to said receiver for processing said RF message; if said number of preamble pulses are less than said second predetermined number of preamble pulses, then automatically terminating power to said receiver after said first predetermined period of time; and if said number of preamble pulses are between said first predetermined number of preamble pulses and said second predetermined number of preamble pulses, then extending said power to said receiver for an extended period of time.