The OP25 Group in 2009/2010 added a software TX for P25 FDMA which was based on the fullrate MBE codec contribution made by Pavel Yazev.

Today with the addition of a halfrate encoder we announce a software TX for two amateur radio digital voice modes (dstar and ysf) as well as 2-slot DMR Base Station support in addition to the existing P25 TX.  The ysf support includes both halfrate and fullrate voice modes.  At this time my impression of the voice quality is very good to excellent in all modes except dstar where it may be considered only fair; we believe the issues with the dstar codec will be very amenable to improvement over time.

The software has been tested successfully using a PC+soundcard connected to an Icom IC-820H via the high-speed (packet 9,600 data input) connector in the back of the radio.  Support for SDR TX devices such as the hackrf and usrp will be added at some point.

To get started, clone the repo, checkout the 'max' branch, and open the doc html file in your browser:

git clone https://git.osmocom.org/op25
cd op25
git checkout max