JST-SH is a 1.0 mm pitch/ disconnectable crimp style connector used on several of the OpenPilot boards. It is used for it small size and reliable connection. Do not confuse it with JST-ZH or JST-XH that are different connectors and not used in the OpenPilot project.
The Revolution is using the JST-SH 4-pin for telemetry, GPS, UART and other IO ports.
CopterControl is using the JST-SH 4-pin for telemetry and the FlexiPort. It also uses a JST-SH 8-pin on the ReceiverPort for PWM or PPM input, and optionally for PPM input and servo output.