Modifying your transceiver does void your warranty. Proceed at your own risk. We are not to blame in any way if you wreck your equipment.
For recieving DRM we had the following equipment:
Remove the upper cover from the transceiver.
Look for the slots for optional CW or SSB filter (backside, left)
It’s labelled: J24 and J23 Bridge the left two pins of J24 – so the software will use this slot as if the SSB filter is installed.
Put a 120 pF capacitor between the right pin of J24 and the right pin of J23. The third pin of J23 is connected to ground.
Connect the DRM mixer module to the two right pins of J23 (ground and 455 kHz IF in) – see page 3 (1) and (2).
You can get the voltage for the mixer from the right backside of the transceiver (only + needed).
For using the DRM receiver you have to use the 2.3 kHz optional Filter setting in Menue N (that’s the reason for the J24 jumper).