This chapter starts with an overview of the requirements of an electrical-link transmitter. Electrostatic discharge protection is required in CMOS processes. The large capacitance it adds severely loads the output driver. The main mitigation strategies are presented here, focusing on T-coil-based compensation, a type of inductive peaking. In Section 1.12, two categories of circuits were introduced, namely CML and CMOS. These give rise to current-mode and voltage-mode transmitters, both of which are presented in this chapter. Impedance control and the implementation of feed-forward equalizers is discussed. A reader who is primarily interested in optical transceiver design should read this chapter before moving on to Chapter 8.