I'm not sure if the protocols used to talk to JMRI are public domain or not, but they are well known, so making a command station compatible with them shouldn't be difficult.
The JMRI Yahoo group should be able to answer your question.....I don't know who created withrottle, but the author of Engine Driver is extremely responsive to questions......his name is Steve Todd, and can be contacted through his web site for Engine Driver.......Google is your friend.
WiThrottle(iPhone) and Engine Driver(Android) are app's that use JRMI code to talk to various command stations. MRC and Digitrax both offer adapters that allow the above throttles to talk directly to their systems without a computer running JMRI... the JMRI code is available as freeware(with some restrictions).
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
I know MRC released a Wi-Fi command station that uses WiThrottle (and Engine Driver?) for control. Does MRC license the use of WiThrottle for the use of their app?