Ars Technica has a detailed article about the long and expensive failure that was the Joint Tactical Radio System (JTRS), a software-defined radio that was going to solve all sorts of comm problems, especially in the coming age of advanced data links.
Interesting story: The A-10C was supposed to be the first Air Force platform to have a JTRS radio. The program was waaaay behind and the cutoff date for getting any datalink in the new A-10 was fast approaching. At the wire, the Air Force took money out from the JTRS program and bought Situational Awareness Data Link (SADL) radios instead. However, much of the design and hardware work had already been done based on the lofty promise of JTRS and there wasn’t money or time to go back and make changes.
So today the A-10C flies with SADL radios, but the switch in the cockpit to turn it on is labeled “JTRS.”