Breakout board IO3-R3 (Revision R3) has digital buffer for STEP/DIR/ENA command signals and as such it is particularly suitable for the connection up to 4 microstep drives MST-107 and/or MST-109 and/or DC servo drives DCS-3010(-HV) and/or DC servo drive with analog output DCS-100-A directly to PC. This breakout board can also be used with all drives that have opto-isolated STEP/DIR/ENA inputs.

On board charge pump prevents undesirable state changes in case of loss of communication with computer.

Breakout board IO3-R3 has two relay outputs that can be used to activate the two output devices (electric motor for the main spindle and/or vacuum pump for chips removing, etc.). Indication of the relay condition is performed by the two LEDs which are located on the board.

One of the relay outputs can optionally be converted to analog output with a voltage range of 0–5 V or 0–10 V. This output could be used to control of spindle motor revolution speed.

Up to 5 limit switches can be connect to the breakout board. Digital inputs for limit switches are opto-insulated and also have input filter for noise suppression.

PC connection is performed via the parallel (printer, LPT) port. Breakout board IO3-R3 has centronics (IEEE1284) connector, so that connection to the PC uses a standard printer cable.

Breakout board IO3-R3 is specially developed to be used with software for generating STEP/DIR command signals via parallel port such as: Mach3, Mach4, LinuxCNC (free), TurboCNC (free), etc.

pdfIO3-R3 User's manual

Photo gallery


Description - function Pin number on the PC
side (connector DB25)
Line type on the
side of PC
X axis STEP 2 Output TTL
X axis DIR 3 Output TTL
Y axis STEP 4 Output TTL
Y axis DIR 5 Output TTL
Z axis STEP 6 Output TTL
Z axis DIR 7 Output TTL
A axis STEP 8 Output TTL
A axis DIR 9 Output TTL
ENA (enable) 17 Output TTL open collector PNP
Safety signal (charge pump) 14 Output OutputCan be optionally switched on and off
Spindle - Rele 1 1 Output Optionally analog output of 0–5 V or of 0–10 V
Coolant - Rele 2 16 Output -
Limit switch 1 (SW1) 10 Input 24V logic
Limit switch 2 (SW2) 11 Input 24V logic
Limit switch 3 (SW3) 12 Input 24V logic
Limit switch 4 (SW4) 13 Input 24V logic
E-Stop - Limit switch 5 (SW5) 15 Input 24V logic


Characteristics Description - Value
Number of axis 4 (X, Y, Z and A-axis)
Axes control By STEP/DIR command lines separately for each axis, common ENA (enable) line for all axis
Output current of STEP/DIR command lines 15mA max
Number of limit switches 5
Number of relay outputs 2
Analog output Optionally 0–5 V DC or 0–10 V DC via jumper
The capacity of one relay output 250VAC/8A max
Supply voltage 15-24VDC/500mA
Dimensions (W x L x H) 165mm x 100mm x 28mm
Weight ~175g

NOTE: specifications are subject to change without notice


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