Nextel LMR is functionality that allows the Direct Connect user to be patched through to the two-way radio systems typically used by the various first-responder agencies (police, fire, military, other federal agencies). So that in regional or national emergencies they can all talk to each other even though each agency may be on otherwise incompatible radio systems. Basically, it's a bridge between multiple incompatible dispatch systems. Nextel was big on this years ago, before Sprint took over. Now that Sprint has jumped onto the Direct Connect bandwagon with their "new" CDMA-based DC, they have to provide matching capability that iDEN had.
See:
http://shop2.sprint.com/assets/pdfs/en/solutions/cas ... »