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)

Thanks, Jeff.
I think that will work.

In the example, between the M5 (stop) and the M4 S10000, (reverse at 10000 RPM).
There would not be enough time for the spindle motor to come to a complete stop, before starting up again.

Looked around and searched the forum...

The spindle motor controller in my machine requires that the motor is stopped before changing direction.
Ideally before changing the spindle direction;
1) Spindle speed is set to 0
2) Wait for the shaft index pulse to read 0 RPM
3) Change the spindle direction
4) Spindle speed back to what it was...

Is there a way to do this with G-Code, or is this something that needs to be done in Mach3?
If in Mach3 any help with that?

Thanks
Derek Vanditmars