Submission by Keith Doxey - The cable marking system employed uses bands of coloured insulating tape to identify the different cables. It is much quicker than some of the adhesive tapes printed with numbers, and more rugged than writing on the sheath of the cable.
From past experience I have found that even when using a permanent marker the ink still gets rubbed off or becomes illegible due to handling or dirt getting on the cable sheath. An added advantage of using coloured tape is that the cables can be identified from across the room...