Technology Update Regardless of whether you look at consumer or industrial applications, whenever a technical breakthrough in available communication bandwidth is achieved, the affected environment and feasible applications change significantly. One recent example was the introduction of the digital subscriber line (DSL) to replace modems for Internet access. With high-speed telemetry systems becoming economically viable in an increasing number of drilling applications, our industry is in a situation similar to that seen at the introduction of DSL. Following the parallel of Internet access via DSL vs. modem, the relevant questions are: How has high-speed telemetry changed the drilling process, and what further changes will we see in the near future? This article first intends to explain why oilfield service companies continually strive for higher telemetry data rates. It then identifies and exemplifies fields of application for both available technologies—high-speed mud-pulse telemetry and wired drillstring telemetry—with two case histories. The conclusion provides an outlook on possible future opportunities and technological developments. Rationale for Higher Telemetry Data Rates Every breakthrough in drilling technology creates an increasing demand on telemetry speed, requiring new telemetry technologies to meet that demand. Consequently, the meaning of high-speed telemetry has changed and will continue to change over time. The most recent major change in drilling technologies has been the rise of increasingly sophisticated measurement-while-drilling (MWD) and logging-while-drilling (LWD) services, e.g., drilling dynamics, formation-pressure testing, high-resolution resistivity and electrical images, and magnetic-resonance measurements. MWD and LWD services reduce the necessity for wireline runs and increase the log quality at the same time because the formation is logged immediately after penetration. In contrast to wireline logging, MWD/LWD tools "see" the freshly cut formation rather than logging it after days of exposure to drilling mud, which results in formation deterioration. They also make downhole drilling-dynamics measurements available in real time, something that has previously been impossible. In the past, one of the major challenges with MWD/LWD services was the ability to transmit all the data gathered downhole. The majority of measurements were written to memory onboard the downhole tool, and only a fraction of the collected data was transmitted in real time to surface. The data then was retrieved from memory after pulling the drillstring out of hole.