19mikel95 wrote

 

So what is happening?

I guess that it is a bad cable. I see the same effect with my TL-SG108E/SG105E when using an UTP cable. Make sure to use a proper shielded CAT.5e S/FTP cable and shielded RJ45 plugs.

19mikel95 wrote

It says its CAT5 UTP, so it might be a faulty cable? Is there any way to asure that its the cable?

Definitely. UTP means »unshielded twisted pair« and this type of cable is not able to transfer 1000 Mbps. As for a quick test, just disconnect the switch from the installed cable, connect it to the other switch using any shielded patch cable you have available and you will see that the switches negotiate to 1000 Mbps.

If this helps to solve your problem, please mark my previous posting as best solution in order to help others with the same problem. Thanks!

19mikel95 wrote

But the other cables are also UDP  and I get 1000Mbps in PC1 for example

If it is a short UTP cable, it might work unless it's a very cheap and crappy cable. If it is a long UTP cable and/or placed in a cable duct near power cables, problems will arise. It even might sometimes work and sometimes not, depending on interference. In theory, CAT.5 UTP cables should work even with 1000 Mbps, but in practice they often cause problems. That's why the standardization organisation did introduce the CAT.5e (extended) category and why most Gigabit cables are shielded in those days.

19mikel95 wrote

Ok thanks so I just buy CAT 6 FTP and change it?

If you plan to use 10 Gbps in the future, use CAT.6 or even better CAT.7. Otherwise for 1 Gbps use CAT.5e FTP, STP or S/FTP; they fit perfectly.

This is one of my patch cables for connecting TP-Link switches and other devices. As you can see, I carefully shield even the plugs. However, those UC900 cables are somewhat expensive, but they work perfectly.