Hello, I have researched this but i hope to get a difinitive answer here. It has been suggested that USB should only be extended 16 feet. Others claim as much as 36 feet. I extended a usb device nineteen feet, one ten foot and one six foot cord plus the three foot device usb cord. The device was originally equipped with a serial input and a usb adapter card was supplied with the machine. The device was working fine for several days but the usb adapter card failed. One of the tiny chips became very hot and there were signs of heat damage on the back of the pcb. The supplier has replaced the card and everything is working once again but i am now using a laptop with only the three foot device cord attached until i can verify that extending the usb could not have caused the failure. And that is my question. What are the consequences if any, of extending a usb device? Would it simply affect transfer rate or cause communication failures or could it actually cause the failure of circuits within the device? Any help would be greatly appreciated. It is truly a pain having to use a laptop near the device. Others have stated absolutely not, using extensions could never cause failure of the circuits, they could only cause performance issues. Are they correct?