Open the control panel of the device and select the digital audio protocol you will be using (ADAT Lightpipe or S/PDIF). On the audio interfaces, connect the digital Out of the master to the In of the slave and the Out of the slave to the In of the master.
Both devices will then need to be synced to the same clock. This can be done by using the internal clock on the master unit and setting the slave unit’s clock to reference the digital connection.
The examples throughout are from a master RME Fireface UCX connected with a slave RME Fireface 400 via ADAT Lightpipe. Specific menu control settings will differ between interfaces.
The next step is to set the routing of the devices. The hardware inputs and outputs of the slave device will need to be sent/received over the digital audio inputs/outputs. On the master side, it will need to route the incoming digital signals to the correct channels as well as sending outgoing digital to the slave device.
Now that the devices are communicating with each other correctly, the last step is to configure the SoundCheck Hardware editor. The device selected will be the master audio interface only for all channels used. For all inputs/outputs on the master device the analog channel will be selected. On the slave device, the channel selected will be either ADAT or S/PDIF. Please note that the Vp and latency of the inputs/outputs are device dependent and will need to be calibrated for each specific audio interface.
In this example, inputs 1-8 are through the UCX hardware inputs which have a latency of 2122. Inputs 9-16 are hardware inputs on the slave 400 which have a latency of 2182. The only device that is selected by SoundCheck is the UCX.
Linked below is the specific set of instructions for connecting an RME Fireface 400 slave to an RME Fireface UCX master.