Digital Subscriber Line (DSL) technology is a copper loop transmission technology, which satisfies bottleneck problems often associated with the last mile between the network and the service providers. This is an introductory tutorial, which covers the basics of the DSL Technology. This tutorial is created for engineers who are new to the DSL Technology. This tutorial provides simple, easy to understand explanations with useful working examples. We will go through most of the modules of DSL, so the reader can also use this as a reference for their projects. There are no specific prerequisites for understanding this tutorial. It will be helpful for the readers, if they are from the telecommunications background. Additionally, it will be advantageous if the reader knows the various equipment used in DSL, its protocols and configurations and other related technologies.