IMTS https://en.wikipedia.org/wiki/Improved_Mobile_Telephone_Service https://en.wikipedia.org/wiki/Improved_Mobile_Telephone_Serv... We used to hack the local

IMTS https://en.wikipedia.org/wiki/Improved_Mobile_Telephone_Service https://en.wikipedia.org/wiki/Improved_Mobile_Telephone_Serv... We used to hack the local system as a youth and make free calls.