Atomos Shogun Studio 2 - Page 59

Quad (Quad Link) mode
When the device set to Quad Link mode, a 4x 3G or 4 x HD SDI signal can be received.
SDI input signals must be connected in the correct order to input IN1, IN2, IN3, and IN4
to use Quad Link. When a Quad Link signal is detected, the indicators for channels 1-4 will
be green.