Voltage Input to an IO port
Frequently Asked Questions
Written by Will Fraser
Updated at February 4th, 2026
Brand:
- AMX
Models:
- NI- Series
- NX-Series
Question:
How do I set up the I/O ports to accept a voltage input?
Answer:
The I/O ports have a voltage present in idle mode, which is used to detect a short in the input.
In order to use a voltage input, the voltage must be lowered to allow the input voltage to be detected.
To do this, use a 2,000 ohm resistor across the desired I/O to shunt the bias voltage to ground.
Wire the input circuit across the resistor to raise the voltage on the I/O back to a level above 5 VDC.
- Maximum input voltage is +12 VDC.
Use the following diagram for reference:
