The computer sends simple commands to the Mini SSC at 2400 or 9600 baud, and Mini SSC generates eight channels of precise, stable servo-control pulses. Servos are primarily designed to drive bellcrank mechanisms, like those that control the angle of control surfaces in a plane, or steering in a car. These mechanisms have a limited range of motion, so a servo's basic design calls for operation over a 90-degree range. However, not all servos can cover a full 180 degrees because of their basic design. It's a surface-mount design, making it more difficult to hand assemble.
Any hobby dealer can help.
Servos are designed to operate from four-cell battery packs supplying 4.8 to 6.0 Vdc. Being designed for battery power, they aren't very tolerant of power-supply noise. An ideal power supply is a linear, regulated 5Vdc supply capable of 1A or more output. The 12V output from the 6.1W supply can be used to power the Mini SSC electronics, replacing the 9V battery too. Servos are held in the last commanded position until instructed otherwise.