I would like to make a cat 5 Ethernet tester and was wondering if a circuit or chip existed where I could use "time domain reflectometer?" I don't just want a continuity tester with led's on the end that light up. I want lengths also and maybe the length of the fault. I heard about this reflectometer on the site below. Thanks in advance.

Snippet below from http://www.vdvworks.com/UncleTed/test.html "Length

Since 568 cables must be less than 90 meters (296 feet) in the link and 100 meters in the channel (328 feet), length must be tested. This is done with a "time domain reflectometer" which is a fancy term for cable "radar". The tester sends out a pulse, waits for an "echo" from the far end and measures the time it took for the trip. Knowing the speed in the cable, it calculates the length. All cable certification testers include a TDR to measure length.

If you have a short or open, the TDR will also tell you where the problem is, making it a great tool for troubleshooting problems."