PMDG will only write the drivers for the allready existing CDU's for the 737 and 747 of engravity (
www.737cockpit.com)
Engravity allready has a full range of hardware for the 737 flightdeck, and now they teamed up with PMDG to make the software link.
I have their 737 cdu and cant wait to use it with PMDG