SIGNET RXTI2 Loop Tester Signet Induction Loop Tester. 1 years warranty / Loop Amplifier & accessories. The RXti has been designed to allow installers, & the non-hard of hearing to test & assess the quality & audibility of the loop system. In order to improve the quality of the receiver, it has a dual inductor system which helps reduce the background noise from computer monitors & fluorescent tubes. The audio response from the receiver is flat from 100 Hz to 13 K Hz. The receiver requires a pair of stereo headphones with 3.5mm jack to listen to the audio signal.