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PMDX-121 Buffered Breakout Board

Model PMDX-121

Buffered Breakout Board with "Charge Pump"

The PMDX-121 has been replaced by the upgraded PMDX-122.
Click here for the PMDX-122.



The PMDX-121 is a motion control breakout board for interfacing with the parallel port of an IBM-PC style computer

  • Supports all signals present on a standard printer port. (8 data, 5 input, 4 output)
  • Buffers signals to protect the PC's printer port.
  • Utilizes standard IEEE-1284 Centronics style printer cable for connection to PC.
  • Provides LED status indicators on the 5 input and 4 output signals.
  • Supports the MACH2 "charge pump" signal to inhibit outputs when the MACH2 software is not running.
  • Inhibits outputs when E-Stop or Fault inputs are asserted.
  • Reports E-Stop to computer on loss of power, E-Stop loop open, or Fault input grounded.
  • Provides one 10 Amp. relay on board for spindle or other I/O output function.
  • Inputs have pull-ups to +5 volts and are filtered to suppress noise.
  • Step and direction outputs from data bits can be common ground or common +5 volts for driving opto inputs.
  • All I/O connections are made via wire clamp screw terminal strips.
  • Auxiliary +5 volt DC output available to power sensors.
  • Three power supply options. (external DC, external AC, or USB port power steal)
  • LED to indicate "outputs enabled" status so "charge pump" status can be seen.
  • Jumpers to control "charge pump" functionality.

Download the full manual in PDF format here (revision 1.4, 212 KB).