A reach back secure communications terminal that offers immediate and secure voice, data and video connectivity to multiple telecommunications networks, high availability and reliable connectivity, total access to vital resources, and secure extension to the home office. Integrated components simplify access to varied networks allowing deployed users to select and connect quickly to a network that best supports their present mission. Commercial or optional NSA Type 1 encryption may be implemented. 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 (2^128 possible keys).