The APEX protocol defines the specification with which all APEX compliant stations must adhere to. It defines both the on-air format of APEX packets as well as the behavior with which compliant stations will exhibit when handling APEX and APRS packets. All APEX compliant stations are expected to use the APEX Paradigm, which should be built-in to any software designed to be APEX compliant out of the box. Despite this non-APEX compliant software can still run the APEX Paradigm but this would only allow for partial compliance with the new network. For this reason the APEX Paradigm is considered separate, though related, to the APEX Protocol.