The quantity of data to be transmitted between devices onboard spacecraft can reach up to several tens of Gb/s, and that volume is constantly increasing. Data transmission is much more than transmitting 0s and 1s. The type of information, the speed, and the signal integrity are key issues which also must be considered. The high-speed links have to be adapted to the environment. When designing the links for spacecraft, engineers have to take into account parameters for outgassing, resistance to radiation, and weight-saving.