CSpire has their own towers within their “footprint”, which is primarily the state of Mississippi along with parts of western Tennessee and south Alabama as well as a small part of the Florida panhandle. If you are a CSpire customer and are outside the coverage “footprint” you are roaming on Verizon towers through roaming agreements between CSpire and Verizon. CSpire and Verizon are CDMA carriers, while AT&T and TMobile are GSM carriers-different technologies. Contrary to popular belief, it’s impossible for GSM phones to work on CDMA carriers (towers) and vice versa-at least that’s what I was told years ago when I worked for AT&T as well as CSpire. The outage Verizon experienced today affected a lot of different regions around the U.S.