I think slowly .. can you imagine how broad an undertaking it would be ?
airlines, aircraft manufacturers, and air traffic control authorities around the world are waiting with bated breath for the FAA to announce the go-ahead of a program to provide U.S. ATC centers with a new generation of digital ground-to-air radios. Called the Multimode Digital Radio program, it is part of the FAA’s NEXCOM (Next Generation Air/Ground Communications) project.
In terms of the overall aerospace industry, the goal of the program seems modest enough: the replacement of approximately 35,000 existing VHF transmitters and receivers with 15,375 VHF TDMA (time division multiple access) radios.