If you took a POE inserter and put the tester on the data only side, that should protect the tester. In theory you can capacitively couple ethernet but I have never tried it.
From: Rory Conaway Sent: Friday, September 8, 2017 11:37 AM To: af@afmug.com Subject: Re: [AFMUG] Basic Ethernet cable tester that survives PoE voltage? https://www.amazon.com/Generic-sfg-Network-Tester-Telephone/dp/B00G55ZGZ8/ref=sr_1_5?ie=UTF8&qid=1504892183&sr=8-5&keywords=ethernet+tester I’ve seen them for $5 but this is still a pretty good deal. Rory From: Af [mailto:af-boun...@afmug.com] On Behalf Of Mike Hammett Sent: Friday, September 8, 2017 10:35 AM To: af@afmug.com Subject: Re: [AFMUG] Basic Ethernet cable tester that survives PoE voltage? Pockethernet? ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP -------------------------------------------------------------------------------- From: "Colin Stanners" <cstann...@gmail.com> To: af@afmug.com Sent: Friday, September 8, 2017 11:57:59 AM Subject: [AFMUG] Basic Ethernet cable tester that survives PoE voltage? I'm looking for a basic-level Ethernet cable tester that only checks the wiremap, gives pass/fail and preferably is <$100 and has a simple TDR. It must survive Canopy 30V PoE voltage as it seems that many of the dead testers that we have in a pile are due to field techs plugging them into live lines. Monoprice $80 tester is OK but definitely does not survive the live lines. A test I'm considering is soldering ~15V zener diodes inside a unit to trigger a PSU's short protection before frying the cable tester...
