Abstract: A private exchange includes a changeover control in order to control existing POTS customer premises equipment access redefinition in a changeover to an ISDN basic rate interface. The exchange includes a first port for connection to a local exchange, a second port for connection to a conventional analog subscriber station, and a controller which is connected with the first and second ports. The controller includes a digital network communication circuit and a cutover device for bypassing the digital network communication circuit in order to directly connect the first and second ports. The controller further includes a detector for activating the cutover device to bypass the digital network communication circuit in response to the first port being connected to a plain old telephone service and for deactivating the cutover device to connect the first port to the second port through the digital network communication circuit when the detector determines that the first port is connected to a digital exchange.