Charles, below is what you need to know about USB cable lengh and the reasons for the limitations. Depending on device response time, cable length can be a HUGE problem.
"The maximum length of a standard USB cable (for USB 2.0 or earlier) is 5 metres (16.4 ft).[34] The primary reason for this limit is the maximum allowed round-trip delay of about 1,500 ns. If USB host commands are unanswered by the USB device within the allowed time, the host considers the command lost. When adding USB device response time, delays from the maximum number of hubs added to the delays from connecting cables, the maximum acceptable delay per cable amounts to 26 ns.[34] The USB 2.0 specification requires cable delay to be less than 5.2 ns per meter (192,000 km/s, which is close to the maximum achievable transmission speed for standard copper cable)."
