A vehicle-based control system and method for use with a barrier operating system that includes a motor, a receiver in communication with the motor, and a remote transmitter for transmitting an activation signal to the receiver. The activation signal includes a radio frequency carrier signal modulated with a codeword for use in activating the motor to open and close the barrier. A vehicle-mounted transceiver receives multiple radio frequency carrier signals, and transmits an activation signal for receipt by the barrier operating system receiver. A vehicle-mounted controller stores the received radio frequency carrier signals, and receives user input identifying an activation scheme having a variable codeword format. The controller generates a variable codeword based on the identified activation scheme, selects one of the stored carrier signals, and controls the transceiver to transmit an activation signal having the selected carrier signal modulated with the generated variable codeword in response to user input.