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SmoothStepper USB / Re: Smoothstepper problem when spindle is on
« on: November 07, 2011, 12:38:40 PM »
USB cables are not all the same.
USB cables for mice and keyboards tend to be not shielded.
Other USB cables say they are USB 2.0 rated, but unfortunately may not be manufactured to the USB 2.0 specification.
Measuring the resistance between the metal shell at each end is a reasonable method to determine if there is a full shield or not.
A lower resistance for a given length of cable would be indicative of a better shield.
A foolproof method is to purchase two or more cables at the same time from the same place, and dissect one to determine if there is a shield and what type.
The best shield has both a metal foil and a wire braid.
Next would be just a metal foil with a drain wire.
The worst would just a single wire, (which really is not a shield at all)
USB cables for mice and keyboards tend to be not shielded.
Other USB cables say they are USB 2.0 rated, but unfortunately may not be manufactured to the USB 2.0 specification.
Measuring the resistance between the metal shell at each end is a reasonable method to determine if there is a full shield or not.
A lower resistance for a given length of cable would be indicative of a better shield.
A foolproof method is to purchase two or more cables at the same time from the same place, and dissect one to determine if there is a shield and what type.
The best shield has both a metal foil and a wire braid.
Next would be just a metal foil with a drain wire.
The worst would just a single wire, (which really is not a shield at all)