Question What type of cable is used to connect the floorboard to the rack unit What is the maximum length Where can I purchase such a cable

This is a standard (non-crossed) CAT 5 cable. This cable can be up to 15 m long. You can buy standard CAT5 cables in any computer shop. However we recommend that you use cables with connectors included in 'XLR'type housing. You can normally purchase this kind of cable from Audio Pro dealers.  For Europe: Canford Audio, - part number 46-9142 is a deployable, 5m (16' 6" approx.) red cable with Neutrik NE8MC1 connectors on both ends (NOT angled) - a variety of lengths and colours are available. Additionally, customers have reported success with (non crossed) CAT6 cables as well.