I would like to run two 100 Mbit Ethernets including a common PoE over a single cable which will be about 3-5m long. Since 100 Mbit needs 4 wires I will need 8 plus some wires for the PoE which is at least 10 or better 12 wires altogether. I wont mind having even more wires (14, 16…).
Do I need a twisted pair for such cable length? Are there any standards for cables (twisted/non-twisted) with more than 8 wires that UTP has? The environment for the setup is a passenger car.
EDIT:
The reason I want to do this is that I am synchronizing 2 devices with Ethernet and am not able to put a switch close to them so I need to run 2 Ethernet lines down to the switch. Also, the 2 devices can't do PoE by themselves – I will inject and split the power from the cable manually by hand (and lead it to DC inputs on those devices for power). The cable I intend will have 2 RJ-45 connectors on each side plus the power lines.
Best Answer
Firstly you will need to check your end devices are 802.3af mode b compliant, otherwise you can't inject the power onto a discrete pair, but instead if they are mode a, you need to put the power onto the data pair which is usually a function of the switch. With regards to UTP. It is possible you might be able to use non twisted cables if the distance is short, your devices will put up with a lot of dropped packets, sub 10Mbit speeds are ok and you don't have too much issue with external EMF sources. But I would be much more inclined to simply run two shielded UTP cables.