p>The Total Access® 850 is an integrated access device designed for cost-effective deployment of voice and data services at the customer’s premises. The Total Access 850 benefits enterprise customers as well as integrated communications providers, such as CLECs, ILECs and ISPs, who require a customer premises device that integrates voice and data functions, and provides a viable migration path from TDM to packetbased technology. The Total Access 850 features remote management, an integrated IP router, and special services slots. Total Access 850 is a modular device with two common slots and eight access slots. Common cards required for operation are a power supply unit (PSU) and a system control unit. System Control Units include either a Bank Control Unit (BCU) or a Router Control Unit (RCU). With a BCU, the Total Access 850 can be configured as a cost-effective TDM channel bank. The BCU activates a T1 network interface and a fractional T1 (DSX-1) interface located on the rear of the chassis. The RCU is another system control option that offers TDM functionality and a migration path to packet technologies including ATM. The RCU also offers an integral IP router and activates a Nx56/64 V.35 port on the rear of the chassis for connecting an additional external data device. Additionally, a variety of user modules are available for use with either the BCU or RCU. Six access slots allow the user to combine a variety of voice and data services. Up to six Quad FXS or Quad FXO access modules can be installed to support up to 24 analog voice lines. Other access modules for data applications include the OCU DP and ISDN U-BR1TE. The other two access slots are for future hardware options. Using local or remote inband management, carriers can turn features, functions and access ports on and off. Easy access to modules, common cards, the power supply, and the optional battery back-up system simplify maintenance procedures. Hot-swappable modules may be replaced without disrupting other units. The four-circuit-permodule design ensures that a maximum of only four analog circuits are affected when replacing a module. A compact, metal chassis suitable for the customer premises or the central office provides added safety and reliability. The 2U design uses a minimum amount of rack space with an 8.5-inch by 11-inch footprint the size of a standard piece of notebook paper. Two Total Access 850 systems can be mounted side-by-side in either 19-inch or 23-inch relay ra