STU IIB and STU III over IP and Serial Links
The Vocality platform offers a very special module designed to allow the traffic from the tactical phones of NATO and the United States DoD to be extended over low bandwidth links. The SVR Card - or Secure Voice Relay Card - is a small option module which houses a powerful DSP which supports the local de-modulation of the audio tones generated by a STU IIB or STU III phone.
A STU phone operates by taking the voice from the telephone handset on the phone, digitising it using a voice compression similar to those used in commercial voice compression products (such as G.729). The data from the voice compression codec is then passed inside the STU phone to the tactical encryptor. The data is encrypted and then passed to another internal component - a dial up modem. However, the dial up modem used in STU phones does not conform to regular commercial modem standards. It is for that reason that STU phones do not operate over regular commercial compressed voice multiplexers or routers.
The Secure Voice Relay card from Vocality International understands the tones generated by STU IIB and STU III phones. The module is available in three formats : 2 channel, 8 channel or 30 channel. These three DSP cards dock onto the Voice Card in the V50plus, V150 or V200 or directly into the V25 to provide support for the modem tones generated by STU IIB and STU III phones.
Because the Vocality units operate efficiently over both serial and IP links, they are as suited to applications such as the provision of tactical phone circuits over iDirect, Vipersat or Inmarsat BGAN networks as they are to applications operating over more traditional serial satellite links such as Comtech EF Data modem links.