For me it has been the other way around
From my screen name some might have gathered I am a ham radio guy. I got into that in the 90's when I high school. One of the lures back then was the autopatch, a telephone radio interconnect.
So for me in 2006 I saw the next frontier as Asterisk telephony.
Seemed by the mid 2000's ham clubs were paying for telephone lines to radio sites that weren't really being used as much as they used to. I saw/see Asterisk as a way combined with 802.11 links to keep those lines to the rest of the world (now really only used for emergency purposes) alive while keeping the monthly costs down.
asterisk app_rpt is a slightly more interesting tool to fuse two-way radio systems and voip. Prior radio systems used expensive, feature limited hardware controllers.
I was also excited by OpenBTS and now its derivatives. The guy behind that, Chris Paget is a ham. Sadly I haven't done much with OpenBTS yet. Seemed the pricey USRP was always the put off. I am hoping someone will re-write openbts to work with the less costly hackrf board.
Village telco is a scalable, wireless local, DIY, telephone company toolkit also by a ham, David Rowe.