Xantech HL85BK Featuring five significant advances in IR control to achieve their remarkable sensitivity, performance and reliability in a wide variety of installation environments. The LCD/CFL friendly Hidden Link IR Kit includes an HL85 table top infrared receiver, 1x4 connecting block and 4 IR emitters. Native carrier frequency transmission circuitry. Nearly every IR system relies on a carrier frequency to “carry” the commands to their destination. Some consumer electronic devices, especially digital cable and satellite TV boxes, are very picky regarding carrier frequency accuracy. At times, they may not accept remote commands unless precisely the right carrier frequency is present.