An integrated access device is automatically configured to conduct packetized voice and data communications between a customer's voice/data equipment and a digital communications switch. For this purpose, the IAD's communication control processor is programmed to perform an automated analysis of the digital communications link and thereby identify communication interface circuits such as DSLAM and voice gateway units, that have been installed by the service provider. It then automatically configures the communication parameters of the IAD for communication compatibility with the communication interface circuits.