Multiplexing signals together onto a common medium for transport is a practice that is an often-overlooked stage of signal processing. The NCTI® Introduction to Multiplexing course defines time division multiplexing (TDM) and frequency division multiplexing (FDM), the two most common multiplexing schemes that have long been used to transport television and telephone signals through their respective transport mediums. An overview of orthogonal frequency division multiplexing (OFDM) is provided as it has now become commonplace in many applications. Optical multiplexing, which falls under the banner of wave division multiplexing (WDM), requires review of fiber-optic technologies before various levels of WDM can be defined. Detailed explanations are provided of how TDM is used in assorted telecommunications protocols that were first used by the telephone industry before being implemented in many broadband cable networks. This course is beneficial for the technician who works in the hybrid fiber coax (HFC) network or headend recognize their network’s capabilities and limitations.