In this article, we present an overview of the physical layer specification of the emerging Asynchronous Transfer Mode (ATM) networks. These specifications concern the complete details of how to ship 53-byte ATM cells from Point A to Point B over a physical medium on a Local Area Network (LAN) or on a Wide Area Network (WAN). While the task of defining the interfaces and line coding of the transceivers over different physical media is ongoing, the primary underlying theme has been the leveraging of existing standards and practices to the maximum extent possible.
