SEM Vista Dual Path US – Verizon, Cat-M System Enhancement Module (SEM) is the most cost-effective and comprehensive solution for migrating compatible Honeywell/ADEMCO VISTA 10P, 15P, 20P, and 21 IP panels to’s award-winning interactive services. The SEM supports the 4G LTE cellular network and optional Broadband Ethernet, ensuring the longest life cycle with the most secure and reliable service. The SEM is now ETL certified, ensuring a high benchmark of safety and sustainability.