F5F Stay Refreshed Power Users Networks Do Ethernet cables made of CAT6 work straight to my computer, but won't they go through my router or switch?

Do Ethernet cables made of CAT6 work straight to my computer, but won't they go through my router or switch?

Do Ethernet cables made of CAT6 work straight to my computer, but won't they go through my router or switch?

A
agarciag1302
Junior Member
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19
09-03-2026, 03:12 AM
#1
Hello! Problem: Cat 6 cables are not working at all. They don't light up anywhere or make any connection on computers through a switch. But they DO work if I plug them directly into the router and PC.
Items: - I bought three 1-meter, two 2-meter, and one 3-meter Cat 6 cables yesterday along with a Dlink switch (model DES-1008C) that has eight ports for connecting to a Wifi Extender.
- Repeater/Extender: Dlink DAP-1530 AC750 Plus Range Extender (manufacturer: LINK).
Connections: 1. I connected the switch directly into the DAP Extender port so it gets internet access. It worked! 2. Then I plugged in two computers to the main switch, and both got working internet. I ran speed tests and used CMD/Power Shell commands with no issues found. 3. The third cable (the 3-meter one) didn't work on any of my machines, not even an old DVR.
Things I tried: - I checked if the "bad" cable was sending any signal, but there were never any lights showing up on computers when using it. - If I use other cables instead of the bad one, I see Green/Orange or Yellow/Orange colors from Ethernet ports, but with the bad one, no lights appear at all.
- I tried the exact same connection as before (using the "bad" cable) while making sure there were no IP Address conflicts... BUT when using that same cable directly between my PC and Router instead of going through the switch, it suddenly works! What does this mean? Can bad cables work only if plugged straight into a router or PC, or am I missing something? I don't want to show them in front of me and have them say "See it works?" just like taking a broken car to a mechanic for free. Is it just how faulty cables act? Thanks!
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A
agarciag1302
09-03-2026, 03:12 AM #1

Hello! Problem: Cat 6 cables are not working at all. They don't light up anywhere or make any connection on computers through a switch. But they DO work if I plug them directly into the router and PC.
Items: - I bought three 1-meter, two 2-meter, and one 3-meter Cat 6 cables yesterday along with a Dlink switch (model DES-1008C) that has eight ports for connecting to a Wifi Extender.
- Repeater/Extender: Dlink DAP-1530 AC750 Plus Range Extender (manufacturer: LINK).
Connections: 1. I connected the switch directly into the DAP Extender port so it gets internet access. It worked! 2. Then I plugged in two computers to the main switch, and both got working internet. I ran speed tests and used CMD/Power Shell commands with no issues found. 3. The third cable (the 3-meter one) didn't work on any of my machines, not even an old DVR.
Things I tried: - I checked if the "bad" cable was sending any signal, but there were never any lights showing up on computers when using it. - If I use other cables instead of the bad one, I see Green/Orange or Yellow/Orange colors from Ethernet ports, but with the bad one, no lights appear at all.
- I tried the exact same connection as before (using the "bad" cable) while making sure there were no IP Address conflicts... BUT when using that same cable directly between my PC and Router instead of going through the switch, it suddenly works! What does this mean? Can bad cables work only if plugged straight into a router or PC, or am I missing something? I don't want to show them in front of me and have them say "See it works?" just like taking a broken car to a mechanic for free. Is it just how faulty cables act? Thanks!

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S
Silmarillion_2
Junior Member
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17
09-04-2026, 06:43 AM
#2
I would prefer if an ethernet cable completely stopped working instead of sometimes failing on specific devices. Usually, something is wrong with the connection at the 8-pin connector. Some parts have slightly too much resistance compared to what ethernet needs. Different machines handle out-of-spec cables differently, which could just be because one end isn't touching right inside the RJ45 plug. I've seen these work fine for a while until they get a little warmer from the machine plugged in. The metal expands and then you lose connection. The more frequent reason is fake cables sold everywhere. There are huge amounts of those flat cables on the market. They have wires that are too thin to be real ethernet cables. Because of the thin wire and other problems, these fakes work on some devices but not others. Besides, because the wire is so thin, it's very easy for the ends inside the plug to become loose. Many companies use standard RJ45 crimping tools that aren't built for thinner wires. Anyway, your best option is probably to buy a new cable. If you had 50 meters of cable, sometimes it saves money to reterminate (splice) it instead of throwing away the whole thing. The wire itself (assuming it's the right size) rarely causes trouble. It costs not much to get good RJ45 ends and the tool to crimp them, but when you start, you'll make too many bad ones anyway. And if you're talking about a short cable, it's cheaper to just toss away a bad one and buy a fresh one.
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S
Silmarillion_2
09-04-2026, 06:43 AM #2

I would prefer if an ethernet cable completely stopped working instead of sometimes failing on specific devices. Usually, something is wrong with the connection at the 8-pin connector. Some parts have slightly too much resistance compared to what ethernet needs. Different machines handle out-of-spec cables differently, which could just be because one end isn't touching right inside the RJ45 plug. I've seen these work fine for a while until they get a little warmer from the machine plugged in. The metal expands and then you lose connection. The more frequent reason is fake cables sold everywhere. There are huge amounts of those flat cables on the market. They have wires that are too thin to be real ethernet cables. Because of the thin wire and other problems, these fakes work on some devices but not others. Besides, because the wire is so thin, it's very easy for the ends inside the plug to become loose. Many companies use standard RJ45 crimping tools that aren't built for thinner wires. Anyway, your best option is probably to buy a new cable. If you had 50 meters of cable, sometimes it saves money to reterminate (splice) it instead of throwing away the whole thing. The wire itself (assuming it's the right size) rarely causes trouble. It costs not much to get good RJ45 ends and the tool to crimp them, but when you start, you'll make too many bad ones anyway. And if you're talking about a short cable, it's cheaper to just toss away a bad one and buy a fresh one.

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