Apollo Mission Control

For most of Project Apollo, Mission Control had a fixed layout. Each station handled a specific, related group of functions; some watched over the spacecraft's hardware, or its software, or its position in space, or over the crew itself. ars expand

Pressing the indicated button in Mission Control sent a digital message to the spacecraft, triggering a relay in the Up Data Link equipment. This activates a relay that bypasses the astronaut's switch, and triggers a relay inside the amplifier. twitter