Here's the sequence of events that take place when you use the RC transmitter:
    
    You press a trigger to make the truck go forward.
    
    The trigger causes a pair of electrical contacts to touch, completing a circuit connected to a specific pin of an integrated circuit (IC).
    
    The completed circuit causes the transmitter to transmit a set sequence of electrical pulses. Each sequence contains a short group of synchronization pulses, followed by the pulse sequence. For our truck, the synchronization segment -- which alerts the receiver to incoming information -- is four pulses that are 2.1 milliseconds (thousandths of a second) long, with 700-microsecond (millionths of a second) intervals. The pulse segment, which tells the antenna what the new information is, uses 700-microsecond pulses with 700-microsecond intervals.
    
    A typical RC signal transmission pulse sequences
    
    Forward: 16 pulses
    Reverse: 40 pulses
    Forward/Left: 28 pulses
    Forward/Right: 34 pulses
    Reverse/Left: 52 pulses
    Reverse/Right: 46 pulses
    
    The truck is constantly monitoring the assigned frequency (27.9 MHz) for a signal. When the receiver receives the radio bursts from the transmitter, it sends the signal to a filter that blocks out any signals picked up by the antenna other than 27.9 MHz. The remaining signal is converted back into an electrical pulse sequence.
    
    The pulse sequence is sent to the IC in the truck, which decodes the sequence and starts the appropriate motor. For our example, the pulse sequence is 16 pulses (forward), which means that the IC sends positive current to the motor running the wheels. If the next pulse sequence were 40 pulses (reverse), the IC would invert the current to the same motor to make it spin in the opposite direction.