Input/Output Modules Industrial Shields Input/Output Modules offer an OptoIsolated Digital Input module and a Relay Output module. The SIO220VAC5T24VDC is an OptoIsolated Digital Input module that converts signals from 12VDC/VAC (220VAC max) to 5-24VDC. This module converts any electrical signal (from 12VDC/VAC to 220VAC max) to a digital signal at 5-24VDC.