TAC Xenta 421A/422A Universal Input and Digital Output Module Manual

This document provides the technical specifications, installation instructions, and operational details for the TAC Xenta 421A and 422A, which are universal input/digital output modules in the TAC Xenta family. It covers their use as standard I/O modules or certified LonMark devices, including input types (digital, thermistor, current, voltage), output relays, LED indicators, manual overrides, communication protocols, and agency compliances.