What are you hoping to achieve? The colour of the cable obviously has no bearing on its suitability to be used for any given purpose. Is this just for housekeeping? "Please Sir, the LX boys have nicked one of my sound CAT5E cables" With my IT Networks Consultant's hat on - IMO I wouldn't bother. In 35 years in networks, mostly in the Finance Industry where the network is critical (I started before Ethernet was released - all point-to-point/star networks back then), I've seen it tried once or twice, and it doesn't take long for the system to break down. CAT5E is CAT5E - they are all electrically the same. People will use whatever cable they have to hand when they need one. By all means code for straight or crossover cables, though that's better done with the cable sheath (red for Xover only), and possibly use coloured Hellerman sleeves to identify CAT5E, CAT6 etc. Now, colour coding the sockets on a patch bay - that's another matter, and can be very helpful.