Secure transmission over satellite phone network

摘要

A reach back secure communications terminal includes a modem to satellite interconnect board that captures DTMF tones, demodulates encrypted modem information, and converts both into an ASCII string for presentation to a data port of a satellite phone, allowing out-of-band control of a non-secure satellite system (e.g., AT command control of a data port) by a user on a secure side of an encryption device, by including the ability to interpret control signals and control the satellite system appropriately. A false dial tone is presented to the encryption device, and the data stream coming from the encryption device is monitored for the presence of dual-tone, multi-frequency (DTMF) tones representing control signals, the DTMF tones are converted to ASCII characters, which are in turn received as control signals by the satellite phone, allowing control of the functions of the satellite system directly from the secure side of the encryption device.

主权项

1. A secure communications terminal,
comprising: a modem interface to accept an in-band encrypted dual tone multi-frequency (DTMF) signal directed to a controlled unsecure device, and to decrypt and demodulate said DTMF signal; a DTMF to ASCII converter module to receive a data stream from said modem interface, to convert DTMF tone to ASCII by removing in-band control signaling from said data stream; and a data port to present said ASCII control string out-of-band to said controlled unsecure device.