terminology question again

[the_digital_dentist]

I have seen plotter and other mechanisms driven by cables.  On the drive motors there is usually a pulley with a helical groove that guides the cable on the pulley so it doesn't cross over itself- the cable is taken up at one end a plays out at the other end of the helical groove after wrapping around the pulley multiple times to ensure lots of friction and no slippage.  What are those pulleys properly called?