When I was starting my pro audio career in the late 1980’s there was little in the way of cable testers on the market. My first cable tester was a Whirlwind Tester. At the time it seemed really useful but it was pretty limited when compared to what is available now. Here is a list of links to some of the cable testers on the market. You’ll notice that some of the designs appear to be exactly the same cable tester with a different model #. You also note that some of these testers can test a large variety of cables (not just audio).
Rat Sound – XLR Sniffer / Sender cable tester
Rat Sound – 1/4″ Sniffer / Sender cable tester
Rat Sound – NL4 Sniffer / Sender cable tester
If there are others that you use and would recommend, feel free to contact me and I’ll add them.