A reach back secure communications terminal capable of GSM network connectivity includes a GSM fixed cellular terminal, and a single whip antenna adapted for user selectable use at any of four distinct frequency bands, e.g., 850, 900, 1800, or 1900. Immediate and secure voice, data and video connectivity is provided to multiple telecommunications networks. Integrated components simplify access to varied networks allowing deployed users to select and connect quickly to a network that best supports their present mission. Networking options include any of PSTN, PBX, GSM (or CDMA or other cell telephone standard), SAT, IP and WiFi. During secure call setup, the reach-back communications terminal exchanges public keys with a remote terminal using FNBDT signaling. Traffic encryption is performed using the NIST approved Advanced Encryption System (AES) standard (Rijndael) and a 128-bit random key (2{circumflex over ( )}128 possible keys).