Trunked Mobile Radio and Packet Data Radio In addition to the public radio telephone service and the paging service, there are other radio services that are not accessible by the public. These radio systems, called the non-public land mobile radio network , have access to frequencies that cannot be used by the public but only by specific users or groups of users. Probably the best known non-public mobile radio service is analogue Private Trunked Mobile Radio (PTMR), which has been used for many y