Wireless interruptible fold back systems are used for talent cueing and crew communications in broadcast and motion picture production. In other cases, the IFB system is used by directors and other management to monitor program audio during a production. UHF wireless IFB transmitter base station with 256 selectable frequencies at 100kHz increments. Standalone or rack mountable with the PRK-2 kit (614.400 to 639.900MHz).