I'm selling my brand new PMDX-422 board and also my PMDX-407 spindle control board if anybody's interested. Here's some info about the board: The PMDX-422 provides all the required buffering, filtering, and pull-up resistors needed to directly connect to stepper motor drivers and the limit/home switches for controlling a machine, plus a 10 ampere relay to control spindle on and off. The PMDX-422 can also be connected to your existing breakout board using a 26 pin ribbon cable and will support the features of that breakout board including (if provided) optical isolation, a "charge pump" and spindle speed control. 1) A single board implementing both the breakout board function AND the motion controller function saves cost and makes installation simpler. Use of option jumpers has been minimized by controlling features via software. 2) The motion control pulse engine generates pulses independent of the host computer timing and provides real time control for smooth step pulse signals up to 100 KHz on 4 axes. 3) Simple USB connection to the host computer supports both CNC operation and firmware updates. 4) Power can be supplied via the USB connection or by a local power source connected to the terminal strips. Also, a jumper can enable or disable +5 volts on pin 26 of the ribbon header interface for use with devices that supply power on this pin. 5) The machine interface provides equivalent signals to one parallel port including 8 step and direction signals, 8 input signals including one dedicated to emergency stop, and 4 output signals including one used to control the on board relay. The first 5 inputs equivalent to those on a parallel port are available on both the terminal strips and the ribbon header. The extra 3 input signals are available only on the terminal strips. In the future these inputs will also function to provide a single encoder input supporting phase signals up to 1 MHz using a hardware quadrature decoder. The index signal will also be supported. This will make lathe CSS and threading possible. 6) The machine interface is available as both pluggable screw terminal connectors and as a 26 pin ribbon header. It is possible to use the terminal strips for limit and home switches while using the ribbon header to connect to a stepper driver. 7) The input signals have a pull-up resistor to allow use with simple mechanical switches. These signals are filtered to reduce noise sensitivity. The inputs will also accept 5 volt logic signals. The first 5 inputs are protected against voltages up to 50 volts above ground. The 3 extra inputs are protected against voltages up to 7 volts above ground. 8) The step and direction outputs are 5 volt logic signals with up to 24 mA of drive current available. The "common" connection for the step and direction outputs is jumper selectable to be either Ground or +5 volts. 9) The relay output provides both normally open and normally closed contacts rated for up to 10 amperes at up to 240 VAC. The normally open contacts are equipped with an arc suppression snubber for longer contact life. An LED is provided to show when the relay is activated. 10) The three logic level outputs are 5 volt signals with up to 24 mA of drive current available. These signals can be used to drive solid state relays. 11) All outputs are turned off in the event of loss of communication from the host, or if the emergency stop input is activated. 12) The emergency stop input is a normally closed circuit for failsafe operation. A break in the circuit will signal an emergency stop. 13) An LED is provided for "Outputs Enabled" to indicate that the unit is ready to run the machine and as an aid in troubleshooting. 14) The board can be mounted against a panel with holes to allow access to the USB jack, pushbutton, and status LEDs. 16) Externally visible LEDs show status of host connection and the SmartBOB-USB board. 17) An externally accessible pushbutton is provided for firmware setup and test. 18) The USB interface is protected against back feeding of power from a local source. 19) The USB interface has jumper selectable termination of the shield conductor of the USB cable. 20) The PMDX-42 is a compact 4.5" by 2.0" board that fits in tight spaces. The PMDX-407 is a basic spindle speed control interface with isolated analog output for use with PMDX SmartBOB-USB boards. Regular version is used as a daughter board on the PMDX-422 Logic power and PWM signal are provided via the daughter board connector. Uses reference voltage from VFD or an external power supply as a source of isolated analog power Sets spindle speed using PWM from CNC control software Single signal interface uses PWM signal for both speed, and On/Off (absence of pulses stops motor) Works with analog interfaces that use 5 volts, 10 volts, or up to 15 volts Provides isolated solid state switch to turn spindle on and off via VFD control inputs. a small relay, or contactors Can work with the relay on a PMDX-422 to provide direction control. Fully isolated interface can be used with non-isolating VFD's and motor drivers Provides speed calibration pot for setting maximum speed LED's for PWM signal and RUN command. Manual run/stop, speed, and direction control are possible using an external pot, relays, and/or switches Optional version will be offered for freestanding operation with other breakout boards. Optional version works with any system that can supply a 100 Hz to 1 KHz PWM signal. Optional version has screw terminals for PWM and 5 to 15 VDC power input The board work's with the newest version of Mach4 and the developers of this board are always updating the firmware to include better features or fix bugs. I was going to use this board with my OX CNC but I sold my OX. I'm selling both of these boards for $145. If your interested send me a message or email me at [email protected]