From what I understand (which maybe wrong, so if I am let me know) either cat5 or 6 will work the same. The diff would be if you are going to be using glan. cat5 and handle 10/100, cat6 can handle 10/100/1000. Hope this helps.
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cat6 is the same as cat5! there is technicaly no cat6. the cat5 is rated on twists perfoot, the cat5+ is rated on hertz. A cat5 is rated at 266kh and these newer "cat6" cabels are rated at 350 to 400kh. So the cat6 is nothing more than a cat5 with a better construction to withstand the EMS shifts and resist "cross talk". This takes the limitation from 100m up to 200m (per the vendor). Thus if your run is under 100m and you have cat5 it is the same as the more expensive cat6 that is forsale. you can run glan, tx, t4 (half and full duplex)all on cat5 the same as the "cat6" cable.
An example is the AT&T cable that is flat, the cable has the same twists per foot, but has also a cable bend every 6". This caused the "cross talk" factor to be half, thus the distance it can hold a singnal can me as high as 250m (that is right 250, done it and I was impressed!). The weight of the actual line is the same 24g