Oops, 4 pairs of course.
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
cable tester
Apr 17, 2020
25 Replies
Of course, but what kind of fault were you describing?
I thought the issue was cable testing, and that mere pin-to-pin DC continuity wasn't all that needs to be tested for cables with twisted data pairs.
John Larkin Highland Technology, Inc
Science teaches us to doubt.
Claude Bernard
I have a RJ45/11 tester like that, super-cheap, like this one
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hide_login_modal=true It has 8 LEDs on both end; energizes each one in turn on the base unit, and shows what lights up on the other end of the cable. For the elderly among us, there's a 'slow cycle' setting :)
Yes, that was my meaning. And also, this should be reasonably automagic, not manual.
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20+ years ago here in SED, John Fields wrote about one of his patents in this area. It could test 25 or more pairs of POTS lines. The transmitter held all other lines low while it pulsed one line high. Line 1 pulsed for 1ms, line 2 for 2ms, and so on. So it would work with a receiver connected to as few as 2 wires, which would detect a positive pulse and a negative pulse of different duration. It couldn't detect split pairs of course, but was good for telco where lines go through multiple wiring blocks and can get mixed up. His patent diagram was all SSI and MSI logic with no CPU but I don't remember the year.
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