This application report introduces the various interface standards used today in modern telecom and datacom systems and describes the methods used to interface between similar and different I/O structures used on Texas Instruments serial gigabit solutions products. The main logic levels discussed in this application report are low-voltage positive/pseudo emitter-coupled logic (LVPECL), current-mode logic (CML), voltage-mode logic (VML) and low-voltage differential signaling (LVDS). This document focuses on these four logic levels, because they are now the most prevalent in today's communications systems. This document deals with the different SERDES devices from Texas Instruments, from input/output structures, various high-speed drivers and receivers, receiver biasing, and termination schemes. Explanations and examples on how to interface different types of drivers and receivers using ac-coupling are also given.