In one embodiment of the present invention, a method for dynamically modifying functionality in a configurable 
communications protocol stack includes, at an interface device, operating a 
protocol stack that includes existing 
protocol stack software operable to process events associated with connections initiated subsequent to the existing 
protocol stack software being activated for new connections. The method also includes communicating new protocol stack 
software from a 
system controller to the interface device, which may be connected to multiple 
telephony resources, for purposes of modifying the existing protocol stack software operating on the interface device. At the interface device, new protocol stack software is received from the 
system controller and is operable to process events associated with connections initiated subsequent to the new protocol stack software being activated for new connections. The existing protocol stack software continues to process all events associated with connections initiated before the new protocol stack software was activated, and the new protocol stack software processes all events associated with connections initiated after the new protocol stack software was activated. The existing protocol stack software, upon completion of all connections initiated before the new protocol stack software was activated, is removed, services provided to the 
telephony resources being substantially uninterrupted by the modification.