The Total Access 850 is an integrated access device designed for cost-effective deployment of voice and data services at the customer’s premises. 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.