Secure Transmission Over Satellite Phone Network

Abstract

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.

1 - 14 . (canceled) 
     
     
         15 . An interface between an encryption device and a satellite phone, comprising:
 a modem interface; and   a control signal converter module to receive a Voice over Internet Protocol (VoIP) data stream from said modem interface, removing in-band control signaling from said VoIP data stream, and to present said removed control signaling out-of-band to a USB data port of said satellite phone.   
     
     
         16 . The interface between an encryption device and a satellite phone according to  claim 15 , wherein said data port of said satellite phone comprises:
 a USB data port.   
     
     
         17 . The interface between an encryption device and a satellite phone according to  claim 15 , wherein:
 said modem interface conforms to V.34 standards.   
     
     
         18 . The interface between an encryption device and a satellite phone according to  claim 15 , wherein:
 said control signal converter module is formed in a programmable integrated circuit (PIC).   
     
     
         19 . The interface between an encryption device and a satellite phone according to  claim 15 , further comprising:
 a FAX/data interface alternatively receiving an output from said modem interface.   
     
     
         20 . The interface between an encryption device and a satellite phone according to  claim 15 , wherein:
 said encryption device is Future NarrowBand Digital Terminal (FNBDT)-compatible.   
     
     
         21 . A method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network, comprising:
 receiving an in-band control signal in a Voice over Internet Protocol (VoIP) data stream from an encryption device;   monitoring said VoIP data stream for presence of a control tone;   decoding said control tone received in-band from said encryption device;   converting said decoded control tone into ASCII control information; and   presenting said ASCII control information out-of-band to said non-secure data network.   
     
     
         22 . A method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network according to  claim 21 , wherein:
 said control tone is a Dual-Tone Multi-Frequency (DTMF) tone.   
     
     
         23 . The method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network according to  claim 21 , further comprising:
 providing a false dial tone to said encryption device.   
     
     
         24 . The method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network according to  claim 21 , wherein:
 said non-secure data network is a satellite phone network.   
     
     
         25 . The method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network according to  claim 21 , wherein:
 said control tone controls a function of a satellite system directly from a secure side of said encryption device.   
     
     
         26 . The method of providing control signals from a user device on a secure end of an encryption device to a non-secure data network according to  claim 21 , wherein:
 said encryption device is Future NarrowBand Digital Terminal (FNBDT)-compatible.   
     
     
         27 . A secure communications terminal, comprising:
 a satellite phone comprising a data port;   an encryption device; and   a modem to satellite phone interconnect board to capture a Voice over Internet Protocol (VoIP) data stream including an in-band control tone, and convert said control tone into an ASCII string, said ASCII string being presented out-of-band with respect to said Voice Over Internet Protocol (VoIP) data stream to said data port of said satellite phone.   
     
     
         28 . The secure communications terminal according to  claim 27 , wherein said data port comprises:
 a USB data port.   
     
     
         29 . The secure communications terminal according to  claim 27 , wherein:
 said control tone is a Dual-Tone Multi-Frequency (DTMF) tone.   
     
     
         30 . The secure communications terminal according to  claim 27 , wherein:
 said satellite phone is controlled from a secure side of said encryption device.   
     
     
         31 . The secure communications terminal according to  claim 27 , wherein:
 said ASCII string is presented out-of-band with respect to a control signal presented to said satellite phone data port.   
     
     
         32 . The secure communications terminal according to  claim 27 , wherein:
 said encryption device is Future NarrowBand Digital Terminal (FNBDT)-compatible.