Question Ethernet Cable Cat6 Works directly, but not through a Switch?

[xxxbabyxxx]

Hello,

Problem:
Cat 6 cable DOES NOT work, nor light up, nor give any connection on any machine through switch, yet works when plugged directly into router/pc connection.

Items:
- I've just bought 3 cat6 cables yesterday & a switch, which I will connect to a Wifi Extender.
- Cables:
1m Cat6
2m Cat6
3m Cat6
- Switch: Dlink DES-1008C 8Ports Switch MANUFACTURER LINK
- Repeater/Extender: Dlink DAP-1530 AC750 Plus Range Extender - MANUFACTURER LINK

Connections:
1. I've connected the switch through the DAP Extender port, to give it internet. (It worked)
2. I've then connected 2x computers to the switch, both got functional internet, ran speed test, and few other connections commands through CMD/Power Shell, and had no issues.
3. The third cable (3m one) would not work on any of the machines, not even on an old DVR.

Things I've tried:
- I've tried checking if the "faulty" cable is giving any signal, but there's never any lights indicator on any of the machines when using it.
- If I use any other cables, I can see Green/Orange or Yellow/Orange etc from Ethernet ports, but with the faulty one there's never any lights.
- I've done the same connection as the one that's functioning using the "faulty cable" yet
- Made sure there's no IP Address conflicts


BUT.. when trying to use that same cable that wouldn't work on any other machine/port on my switch, it suddenly works if I use it between my PC & Router directly.

What does that indicate? can faulty cables work only through direct connection or something? am i missing something?

I don't want them to test it infront of me and be like "see it works?" just like bringing your broken car to the mechanic, only for it to work when you're there XD.

is it simply a behavior of a faulty cable?

Thanks.

 

[bill001g]

I would be nice if ethernet cable completely failed rather than sometimes work on some devices.

What is likely is some connector out of the 8 has slightly higher resistance than the requirements for ethernet. Some devices tolerate out of spec cable more than others.

This could be as simple as one of the ends is not making proper contact inside the rj45 plug. You sometime see these work and then they get a littler warmer from the machine they are plugged into and the metal expands and you lose connectivity.

The much more common reason you see is all the fake cable being sold. There is massive amounts of that flat cable sold. It all has wires much too thin to meet the specifications to be a actual ethernet cable. Because of the thin wire and other issues these fake cable work on some devices and not others. In addition because the wire is so thin they tend to be much more suseptible to the ends being loose internally. Many companies use standard rj45 crimp on which are not designed for the thinner wire.

In any case you best option is likely to buy a new cable. If you were talking a 50 meter cable then you sometime can save money by reterminating the cable. The wire itself (assuming it is the correct size) seldom is the issue. The cost of the rh45 ends and the tool to crimp them on is not real high but you will make a bunch of bad ones when you first start and when you are talking short cable it tends to be cheaper to just toss a bad cable and buy a new one.

 

[xxxbabyxxx]

I would be nice if ethernet cable completely failed rather than sometimes work on some devices.

What is likely is some connector out of the 8 has slightly higher resistance than the requirements for ethernet. Some devices tolerate out of spec cable more than others.

This could be as simple as one of the ends is not making proper contact inside the rj45 plug. You sometime see these work and then they get a littler warmer from the machine they are plugged into and the metal expands and you lose connectivity.

The much more common reason you see is all the fake cable being sold. There is massive amounts of that flat cable sold. It all has wires much too thin to meet the specifications to be a actual ethernet cable. Because of the thin wire and other issues these fake cable work on some devices and not others. In addition because the wire is so thin they tend to be much more suseptible to the ends being loose internally. Many companies use standard rj45 crimp on which are not designed for the thinner wire.

In any case you best option is likely to buy a new cable. If you were talking a 50 meter cable then you sometime can save money by reterminating the cable. The wire itself (assuming it is the correct size) seldom is the issue. The cost of the rh45 ends and the tool to crimp them on is not real high but you will make a bunch of bad ones when you first start and when you are talking short cable it tends to be cheaper to just toss a bad cable and buy a new one.

Thank you for your reply!

It's interesting that some devices allow "Out of Spec cables" and maybe that explains how it worked directly from my Router to PC, but would not be accepted from Switch to any other computer/device.

Could the length (3m) play any role with it being out of spec and be accepted? ik that 3m is too short for Cat6 but I'm worried they'll cut me the same cable & have it fail again when I get home & try it.

 

[bill001g]

I forget what the standard says is the minimum length. I think it is 1 meter but I am not sure why there is that restriction. I have made a number of cable less than 1ft for use in a patch panel and they work fine.

It depends on where you buy cables from. A profession cable place will have a meter that can certify cable. Many times these cost close to $1000 but they are very precise instruments that will test to be sure it really is a ethernet cable.

Places that do not specialize in cables tend to not want to pay for these tools and might use the ones normal consumers buy off amazon for $20 that will check very basic cable construction. It could be you just got unlucky even the best guy can make a bad cable now and then.

Key here is the wire must be pure copper wire (no CCA) and have wire size AWG 22-24. This information tends to be printed on the side of the cables.

 

[xxxbabyxxx]

I forget what the standard says is the minimum length. I think it is 1 meter but I am not sure why there is that restriction. I have made a number of cable less than 1ft for use in a patch panel and they work fine.

It depends on where you buy cables from. A profession cable place will have a meter that can certify cable. Many times these cost close to $1000 but they are very precise instruments that will test to be sure it really is a ethernet cable.

Places that do not specialize in cables tend to not want to pay for these tools and might use the ones normal consumers buy off amazon for $20 that will check very basic cable construction. It could be you just got unlucky even the best guy can make a bad cable now and then.

Key here is the wire must be pure copper wire (no CCA) and have wire size AWG 22-24. This information tends to be printed on the side of the cables.

It says this on the cable: 3m Cat 6. U/UTP PVC 4 PAIRS 28-16 T 0029M MADE IN TAIWAN

I am hoping a new Ethernet cable will fix it :/ I don't have another long one to test to rule it out for now.

 

[xxxbabyxxx]

I would be nice if ethernet cable completely failed rather than sometimes work on some devices.

What is likely is some connector out of the 8 has slightly higher resistance than the requirements for ethernet. Some devices tolerate out of spec cable more than others.

This could be as simple as one of the ends is not making proper contact inside the rj45 plug. You sometime see these work and then they get a littler warmer from the machine they are plugged into and the metal expands and you lose connectivity.

The much more common reason you see is all the fake cable being sold. There is massive amounts of that flat cable sold. It all has wires much too thin to meet the specifications to be a actual ethernet cable. Because of the thin wire and other issues these fake cable work on some devices and not others. In addition because the wire is so thin they tend to be much more suseptible to the ends being loose internally. Many companies use standard rj45 crimp on which are not designed for the thinner wire.

In any case you best option is likely to buy a new cable. If you were talking a 50 meter cable then you sometime can save money by reterminating the cable. The wire itself (assuming it is the correct size) seldom is the issue. The cost of the rh45 ends and the tool to crimp them on is not real high but you will make a bunch of bad ones when you first start and when you are talking short cable it tends to be cheaper to just toss a bad cable and buy a new one.

I've found another Cat6 cable around, it was an old 5m one that I had and it worked perfectly.

I guess you're right it must've been a faulty cable and that's why it wouldn't be accepted on the switch/any device other than direct PC/Router connection, yet all other cables worked.

Thanks bill001g 🙂❤️ this can be closed! (for some reason I can't mark this as a "SOLVED" thread? nor pick the best answer? if any mod can do that for me it would be nice, ty 🙂)"