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SVZ-B: Wideband Voice encryption unit

SVZ-B or wideband voice encryption unit; manufactured by Crypto AG, Zug.

For many years, the American made SE-227 and SE-412 radios had to be used without encryption; code tables, obfuscation lists and „coded speech“ had to be used to make the content of a message incomprehensible to third parties.

The situation changed when the SVZ-B digital voice encryption unit was introduced in 1984: the SVZ-B allows fully encrypted and cryptographically secure communication.

SVZ-B

Technical data

Power supply

Dimensions

  • 285 x 68 x 280 mm, 4.0 kg

Accessories

  • Relay control units RAS-227 and RAS-412 for encrypted communication via relays.

SVZ-B

Operation

The SVZ-B can be connected to the SE-227 and SE-412 wireless sets via the X-Mode wideband interface, the RAS-227 and RAS-412 relay switching sets allow direct relay operation without switching, the previous CX-4656/GRC relay cables could no longer be used on encrypted SE-227 relay connections.

Two keys can be entered on the SVZ-B using the numeric keypad and the user can easily change between both of them; a NiCd battery is used to keep the memory contents when the set is powered off.

The SVZ-B is connected to the transceiver with a 19-pin plug. The microtel is connected at the top left, next to the volume control to the right. The switch underneath can be used to switch between clear mode, key 1 and key 2.

The two stored cryptological keys can be deleted by pressing the key combination 0 and * or they are automatically deleted when the set cabinet is opened.

Technical principle

SVZ-B The audio signal is converted into a 9 kBit/sec data stream using adaptive pulse code modulation (APCM); together with synchronisation pulses, this results in a 9.6 kBit/s data stream.

The key generator generates pseudo-random numbers at the same speed, they are mixed with the data stream and fed to the transmitter via the X-mode interface.

The coded signal, which can only be perceived as noise, is mixed on the receiver side with the same pseudo-random number data generated by the key generator, resulting in a data stream identical to the original audio signal, which is converted into an audible audio signal by a digital-to-analogue converter.

Components

SVZ-B The set is completely solid state.

Development

The SVZ-B was developed by Crypto AG in Zug in 1980/84.

The remote-controlled SVZ-B L Flz was developed as an alternative for light aircraft and helicopters.

Deployment

The sets were procured in 1983/84 and were in service with the troops from 1986 until 2002; they were widely used in radiotelephony, as standard, only network subscribers with increased security requirements were equipped with the classified SVZ-B.

Due to the classification, the sets did not end up in collector's hands after being liquidated.

Technical documentation

Further information

en/svz-b.txt · Zuletzt geändert: 2024/01/18 15:39 von mb