Digi RF products are FCC approved for use in fixed base station and mobile applications. As long as the antenna is mounted at least 20cm (8in) from nearby persons, the application is considered a mobile application. If the antenna will be mounted closer than 20cm to nearby persons then the application is considered "portable" and requires an additional test performed on the final product. This test is called the Specific Absorption Rate (SAR) testing and measures the emissions from the radio modem and how they affect the person.
Digi has tested the modems and verified that they pass the necessary SAR tests but the FCC requires that this test be redone on the final product.
For more information please refer to the FCC Certification section of the product manual for your radio.