Abstract: In a system comprising multiple electronic (radio frequency) identification interrogator devices, which are used to activate and to receive identification code information from one or more passive transponder devices, activation signals are synchronized and adaptively timed by a master interrogator. The master interrogator generates a synchronization signal containing frequency, phase, and cadence information, and uses this synchronization signal to generate its own activation signal. The master interrogator also conveys this synchronization signal to slave interrogators, where it is used to generate each slave's activation signal. Each slave interrogator conveys to the master interrogator its transponder detection status information, and the master interrogator modifies the synchronization signal's cadence in compliance with timing requirements of ISO Standard 11785.