From Newsgroup: alt.os.linux

On 2025-05-29, Java Jive <java@evij.com.invalid> wrote:

On 2025-05-29 19:48, Theo wrote:

In uk.comp.os.linux Java Jive <java@evij.com.invalid> wrote:

As I understand, the two halves of those testers slide apart and you can >>> put one half at each end to perform the test.

Do you need to see both ends to run the test, or is one sufficient?

I saw a video showing that a green light on each part scans down the numbers >> 1 to 8 then 'G'. But I'm not sure if you are testing that the lights match >> at both ends, or if a fault is only shown at the end that detects it.

(eg if you had open circuit at one end and a short at the other, what would >> it tell you?)

Well, I've not used one, so I'm guessing based solely on electronic
logic. Hopefully, if I'm wrong, someone will correct me.

The scanning light testers give indication only that ther terminals
are connected in the correctr order, that catch more than 99% of all
miswired connectors.... because usually you get one pair right.

1) If the cable was miswired by crossing two cables, then I'd expect
the lights at one end, most probably the remote end, to light in the
wrong order.

Exactly that happens. If the numbers "555" and "4017" mean anything to
you you can probably guess how these devices are built.

2) If you have a short at one end, I'd expect two lights to be on at
the same time at least at that end, probably at both.

Both ends show both lights at reduced brightness

3) If you have an open circuit, I'd expect the corresponding light at
one end or the other to fail to light.

Yeah the unpowered end gets no light, the powered end gets a slightly
brighter light. (assuming that the receiver is attached at the other
end)
--
Jasen.
🇺🇦 Слава Україні
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From Newsgroup: alt.os.linux

On 2025-07-01 10:10, Jasen Betts wrote:

On 2025-05-29, Java Jive <java@evij.com.invalid> wrote:

On 2025-05-29 19:48, Theo wrote:

In uk.comp.os.linux Java Jive <java@evij.com.invalid> wrote:

As I understand, the two halves of those testers slide apart and you can >>>> put one half at each end to perform the test.

Do you need to see both ends to run the test, or is one sufficient?

I saw a video showing that a green light on each part scans down the numbers
1 to 8 then 'G'. But I'm not sure if you are testing that the lights match >>> at both ends, or if a fault is only shown at the end that detects it.

(eg if you had open circuit at one end and a short at the other, what would >>> it tell you?)

Well, I've not used one, so I'm guessing based solely on electronic
logic. Hopefully, if I'm wrong, someone will correct me.

The scanning light testers give indication only that ther terminals
are connected in the correctr order, that catch more than 99% of all miswired connectors.... because usually you get one pair right.

1) If the cable was miswired by crossing two cables, then I'd expect
the lights at one end, most probably the remote end, to light in the
wrong order.

Exactly that happens. If the numbers "555" and "4017" mean anything to
you you can probably guess how these devices are built.

2) If you have a short at one end, I'd expect two lights to be on at
the same time at least at that end, probably at both.

Both ends show both lights at reduced brightness

3) If you have an open circuit, I'd expect the corresponding light at
one end or the other to fail to light.

Yeah the unpowered end gets no light, the powered end gets a slightly brighter light. (assuming that the receiver is attached at the other
end)

Thanks for the detailed explanation.
--

Fake news kills!

I may be contacted via the contact address given on my website: www.macfh.co.uk

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From Newsgroup: alt.os.linux

On 2025-07-01 19:46, Java Jive wrote:

On 2025-07-01 10:10, Jasen Betts wrote:

On 2025-05-29, Java Jive <java@evij.com.invalid> wrote:

On 2025-05-29 19:48, Theo wrote:

In uk.comp.os.linux Java Jive <java@evij.com.invalid> wrote:

As I understand, the two halves of those testers slide apart and
you can
put one half at each end to perform the test.

Do you need to see both ends to run the test, or is one sufficient?

I saw a video showing that a green light on each part scans down the
numbers
1 to 8 then 'G'.  But I'm not sure if you are testing that the
lights match
at both ends, or if a fault is only shown at the end that detects it.

(eg if you had open circuit at one end and a short at the other,
what would
it tell you?)

Well, I've not used one, so I'm guessing based solely on electronic
logic.  Hopefully, if I'm wrong, someone will correct me.

The scanning light testers give indication only that ther terminals
are connected in the correctr order,  that catch more than 99% of all
miswired connectors.... because usually you get one pair right.

1)  If the cable was miswired by crossing two cables, then I'd expect
the lights at one end, most probably the remote end, to light in the
wrong order.

Exactly that happens.  If the numbers "555" and "4017" mean anything to
you you can probably guess how these devices are built.

2)  If you have a short at one end, I'd expect two lights to be on at
the same time at least at that end, probably at both.

Both ends show both lights at reduced brightness

3)  If you have an open circuit, I'd expect the corresponding light at
one end or the other to fail to light.

Yeah the unpowered end gets no light, the powered end gets a slightly
brighter light. (assuming that the receiver is attached at the other
end)

Thanks for the detailed explanation.

Yeah, I crimp very few cables, so I have not seen some of the failure
modes Jasen describes, and the booklet doesn't say either.
--
Cheers, Carlos.
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