Automated time-domain reflectometers (TDRs) dubbed the CT100 series have debuted for distance-to-fault and other transmission measurements in modern analog/RF and digital communications systems. CT100 Series TDRs feature horizontal cursor resolution of 0.003 in. (75 microns) and system rise times as fast as 60 ps (20 to 80 percent). With sequential sample rates to 250 kHz (more than 500 waveforms per second), these instruments are able to capture rapid transient faults. The TDRs come with CT Viewer, a full-featured TDR waveform-analysis software package designed for Microsoft Windows XP/Vista. CT Viewer lets the operator rescale, compare, and perform math transforms on stored TDR waveforms. According to Mohr and Associates, the CT100 is the only commercially available replacement for the popular, discontinued Tektronix 1502C TDR.