USB Extension Cords - Communication Roadblock for Plotters

I have now had two separate users contact me about those USB extension cables.  Both users tell me that they had their plotter printing fine, but wanted to move the plotter further from the computer and tried using a USB extension. Surprise! It stopped working. Why? Because even though their USB to parallel cable cord was BI-DIRECTIONAL as I've often preached in this blog, their extension wasn't...so the back and forth communication that the plotter needs to keep the image printing stops at the extension...Both users reported that when they took the extension out of the circuit everything started printing again. 

If anyone has found a bona fide USB extension cord that is BI-DIRECTIONAL contact me and tell me all about it...I'll publish the info here.