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I'm looking to extend two USB 2 devices with one 5 meter long cable. From what I've read, one can run USB 2 fine over Cat5e cable (as long as it's <5m). My question is whether it really matters if the cable is Cat5e or regular Cat5. I couldn't find much on the matter.

Also, I take it doesn't matter if I power both devices from a single USB power line (saving me 2 lines from the ethernet cable).

Running two USB cables over one ethernet line saves me from having an ondevice powered USB hub (lighter) and having two USB cables running next to each other.

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    \$\begingroup\$ I believe Cat5 has less maximum capacitance than 5e, but for 5m they should be close to the same. \$\endgroup\$ – Scott Seidman Apr 26 '18 at 20:42
  • \$\begingroup\$ Okay, thank you Scott. I will just give it a go then. \$\endgroup\$ – LongLog Apr 26 '18 at 20:58
  • \$\begingroup\$ If you should specify the targeted speed of your devices, the answers might be quite different. \$\endgroup\$ – Ale..chenski Apr 27 '18 at 0:29
  • \$\begingroup\$ I thought nobody was still producing old cat5. Are you sure what you have isn't actually cat5e? I haven't seen a true cat5 since a long time. \$\endgroup\$ – dim Apr 27 '18 at 4:46
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Actually, the cables can be much longer than 5m if you mean HS transmission, see SuperUser Maximum length of a USB Cable.

However, running two USB2 links over two unshielded pairs inside one standard CAT5/6 cable will create substantial cross-talk between two channels, especially over such long cable. If USB devices are HS (480 Mbps), two host ports might see unwanted/unexpected signals, and shut themselves down. More, CAT5/6 cables have 10% higher differential impedance, which increases inter-symbol interference and makes more noise. And lower quality cables (CAT5) make the situation worse. So I am not sure if two USB2 channels over the same UTP networking cable is a good idea.

If anything, you should try Shieleded Twisted pair cable, like this one:

enter image description here

You might have a better chance with that. And obviously, higher electrical quality of CAT6 cable will be quite beneficial for USB HS signals.

Regarding power over USB at 5m distance over UTP, the common cable wires are not that thick, 28AWG, so the voltage might drop substantially. And you will need individual VBUS wires for each USB link, so you can't use a pair of them to increase conductivity.

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  • \$\begingroup\$ Sorry for the late reply. I was indeed successful in running two USB cables over one ethernet 5e cable. I think there was indeed some interference as it would not always work 100%, but it was good enough for a test run. Your suggestion to use the shielded one is very good. \$\endgroup\$ – LongLog Dec 23 '18 at 17:09

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