rcuits required</h4>
<p>
   Note that all of the output controllers have strict limits on the amount
   of current they can supply to the feedback device.  This is usually around
   10 mA, which is <i>very</i> little current, only enough for something like
   a small indicator LED.  Devices that draw more current than that - which
   is practically everything in a pin cab - require some kind of "booster"
   or amplifier circuitry between the output port and the device.  The details
   of those circuits are 