The Fastlink/Multilink transmitters stay keyed for a minimum of 5 seconds, after which the transmitter will not transmit again until power is removed. Once power from the transmitter is remove, the transmitter is ready for more transmissions. The transmitter shuts down after 5 seconds so that a run-away transmitter will not jam the frequency on which it transmits.
FCC rule Part 90 states that a transmitter cannot transmit continuously for more than 3 minutes
