An integrated system concurrently connects voice and data communications devices used by small and medium sized businesses to a network T1 data line terminating at the customer premises. A system chassis includes multiple slots and backplane connectors for removably receiving a bank controller unit (BCU), power service unit (PSU), and one or more different types of smart and dumb voice and data access modules that provide the functional interface to the customer premises equipment. The BCU controls the operation of the system, which can be configured by the customer through an external terminal interface.