Part of ADTRAN's Total Access System, The Total Access 850 is modular carrier-class Integrated Access Device (IAD). The Total Access 850 offers a wide variety of features and interface options for T1 TDM and packet networks such as T1 ATM and DSL. Scalable and economical, this IAD allows users to select from a wide variety of voice and data options for flexibility and ease of configuration. This platform offers an integral router, V.35, and DSX-1 interface port, and it can support up to 24 analog FXS ports by utilizing the six access module slots. With the Total Access 850 users can easily migrate from TDM to packet circuits, as network requirements change. An optional 8-hour battery backup system is available to protect uptime in case of a power outage.Total Access 850 Upgrade Shelf enables upgrade for Total Access System 750 users to the Total Access 850. Included are Total Access 850 (1200375L1) and T1 RCU (1200376L1).