Network engineer of 20+ years here, but I'm struggling with this 'fished' terminology. Does it mean when a cable is pulled through on a piece of string?

Yep! Might be a more common term among electricians.

And cable techs.

> Does it mean when a cable is pulled through on a piece of string?

That is often exactly what is meant. The problem of running Ethernet through existing structures has spawned a bunch of tools, including glow-in-the-dark "fish tape."

The process is often brutal, and looks like tug-of-war when it takes a couple men to pull the bundle through a couple 90 degree turns. As such, we have "plenum" cable, which is much tougher than typical patch cable, because the latter would just get shredded inside the structure, or snap when pulled with a few hundred lbs of force.

With an important note that the real purpose of plenum cable and the cause of its stiffness is for meeting fire safety regulations when used in plenum spaces. It just happens to also be convenient that this usually makes it a bit sturdier to work with.

For really long runs in industrial settings they have battery powered pullers that use a really strong string.

> The problem of running Ethernet through existing structures has spawned a bunch of tools, including glow-in-the-dark "fish tape."

None of these tools are new (well, the glow fish sticks I think are a recent innovation) or unique to ethernet. Electrical wire is installed the same way, eg. in conduit. There's even a special lube for making your wire slide through the conduit easier.

I remember seeing glow rods 10-15 years ago in the cable industry.

AFAIK plenum cable also needs a certain fire resistance rating. "Plenum" means something like a hidden space where air flows.

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In my case, when I upgraded from Cat5 to Cat6, I taped on to the existing 5 and used it to pull the 6 through the attic and down the wall. In the attic, you usually use a string, with a weight of some kind attached (if it's a new install), to drop down the wall seal plate, which you've drilled a hole into, down to the hole you've already carved out for your cable box near the baseboard area.

I tried recrimping the connectors. It did nothing.

It's definitely pair damage, but could also be a drill or other nick (ie: making potlight holes), or even stapled wire.

Recrimping is always the best first step. Sometimes running 2.5gb instead of gigabit will help too.

I had to buy a new crimping tool a while ago because I couldn’t find the one I had from a few years before.

I ended up buying a small kit containing both crimping tool and a couple of additional tools.

One of the tools included is an Ethernet cable tester. It has two parts; one for each end of the cable. The part on one side is powered by 9V battery (same one used in smoke detectors etc).

You connect the parts to the RJ45 plugs of each side. And it has individual LEDs for each of the eight leads in the cable. They are lit up in sequence. Any that don’t light up means that that pin is not properly connected, or the cable is broken.

And using that tool is how I found out the reason one of the router ports report 100M instead of 1000M connection. Half of the leads on the cable connected to that port are damaged or not properly connected! And the four that are working are the ones needed for 100M.

I remember that when I originally crimped that cable years ago I was struggling for quite a while, getting no connection at first until after a couple of attempts I got it connected. I didn’t notice at the time, nor for a long time after, that it was only a 100M connection. And it took until I had this tool to figure out the why of it being only 100M.

You also might have crimped it for 100Mbps specifically. 100Mbps ethernet only uses 2 wire pairs, not all 4. It was common, and intended, to carry 2 separate connections through a 4-wire cable. Ethernet and up to two landlines (or a 2-pair landline, which existed) was also a good combination.

I had a lot of trouble with this when having my contractors run cat6 in my house during a recent renovation. Their electrician kept saying "it's done!" and then I'd test it and find that I was getting only 100mbps. Then they'd re-terminate the ends and a few more of the runs would get full speed when I re-tested. Repeated this cycle a few times until they all worked.

I had my electrician pull the CAT6A in my current place, but then I terminated it all myself.

That would 100% been the right move. Some friends of mine with networking and ops backgrounds told me, "never trust an electrician to do low-voltage work right." After my experience with this one, I think I should have listened!

Absolutely. I've seen two examples of electricians using wire nuts to splice two runs if UTP wire together. There's also a general disregard for keeping the pairs twisted as close to the termination as possible.

I came here to say that - I wonder if one of the ends just went bad and needed re-crimping.