Secure voice data unit
is an encryption/decryption device
and data signals,
developed around 1997 by Harris (now: L3Harris)
in Rochester (NY, USA).
It was commonly supplied as part of a 400 Watt HF radio station,
and used over narrowband HF channels.
Intended for non-Type 1 applications, it allows 3
unique algorithms to be selected.
The unit is also known as NSN 5820-01-469-8797.
The device has interfaces for Ethernet, RS-232 and fixed-base and
handset audio, a versatile processor platform,
an LPC-10 vocoder at 2400 baud,
a Harris CITADEL cryptographic engine,
a single-tone HF narrowband modem
with a speed of 75 - 4800 baud and a data-directed equalizer that minimises
the effects of multi-path delays.
The device is housed in a rugged (grey) die-cast aluminium enclosure,
and was part of the Harris RF-5800 Falcon II family of devices.
All controls, a
12-button keypad and a backlit Liquid Crystal Display (LCD),
are located at the front panel.
Also at the front is a standard
U-229 AUDIO socket
for connection of a handset,
headset or fixed audio unit, a 10-pin NF10 socket for connection of a
key FILL device
and/or the Crypto Ignition Key (CIK), and a 19-pin DATA socket.
The 4-pin power socket, one further 19-pin DATA socket, a 10base 2 thin
ethernet socket (BNC) and a GROUND terminal, are all located at the
The RF-5811 was registered in the NSN database in 30 November 1999  1
and was first tested in an operational context in 2003 and 2004 with the
Standby High-Readiness Brigade (SHIRBRIG)
of the United Nations (UN),
which existed from 1 January 2000 to 30 June 2009 .
It was used to replace the UN's existing
and HC-4220 (fax)
encryptors, and provide the
participating SHIRBRIG countries with
a common – compatible – interface for sending secure voice and data traffic
over HF radios and satellites.
Other uses of the RF-5811 are currently unknown.
The unit shown here has a manufacturing code of week 23 1997, but this
conflicts with the date codes on some of the chips, which are from
1998 and 2000. It is therefore likely that the design was modified
one or more times before the first units were delivered in 2000.
The diagram below provides a quick overview of the controls and
connections on the body of the RF-5811. Power, the local network
and any local (parallel or serial) data devices (i.e. the RED side)
are connected to the sockets at the rear. The radio should be
connected to the DATA socket on the front panel, whilst a handset
(or equivalent) is connected to the 6-pin U-229 AUDIO socket.
SHIRBRIG was a Danish-led initiative, associated with the United Nations (UN)
aimed to create a standby force ready for peacekeeping, formed as a result of
the Rwandan genocide of 1994 . It had permanent headquarters in
Høvelte (Denmark) and was initially led by Major General Patrick Cammaert of
the Royal Netherlands Marine Corps .
The brigade was active from 1 January 2000 to
30 June 2009. During its existence, the following countries participated
in the brigade:
The RF-5811 is housed in a die-cast aluminium enclosure that measures
250 x 183 x 80 mm and weights 2116 grams. The centre part
of the front panel can be removed. The interior is accessible from the rear,
and requires the four black screws at the corners of the rear panel
to be loosened.
After loosening these screws, the rear panel – that is sealed with a watertight
gasket – can be removed. Mounted to the
inside of the rear panel is a PCB on
which all rear connections
are mounted. This PCB is connected to the front
panel via a 50-wire high-density ribbon cable.
On the board are the two transformers for the 10base2 Ethernet interface,
and some filtering for the data lines. Also on this board is a
that is held in place by a metal bracket. This battery is responsible
for retaining the KEKs
and TEKs in the unit's internal CMOS memory.
Also connected to the front panel – which acts as a central hub – is a
that contains the actual circuitry. It is divided in two
sections – marked compartment A and B – and is slotted into the front panel by
means of two wide multi-pin connectors; one for each compartment.
The tray is held in place by two recessed screws that are located near the
short sides. After loosening these screws, the
entire tray can be pulled out
towards the rear. Note that before doing this, it is advisable to
removed the rear panel first, by disconnecting the 50-pin ribbon cable.
The tray is mounted upside down
(when looking into the rear end of the
device. Inside it are four PCBs – two for each compartment – separated
by a metal panel. There are no direct connections between the two
holds a PCB with a Motorola MC68331
processor, an Altera Flex FPGA and an LSI-chip marked
It is mounted on top of another large PCB
with the same processor and FPGA,
plus a TMS-320 Digital Signal Processor (DSP) made by Texas Instruments.
This DSP is probably used for
the implementation of the LPC-10 speech processor.
LPC-10 is a vocoder that allows digitised speech to be transmitted
through a narrowband channel (of 800 to 2400 bits per second), at
the expense of speaker recognition. The B-side of the tray holds two
one with another TMS320 DSP,
and one with a
Motorola XPC860 multi-I/O controller
with built-in 32-bit processor. The latter provides
the DATA and ETHERNET ports.
At present, no further information about the Harris RF-5811 is available.
We are currently looking for brochures, operating manuals, technical
documentation and further examples of its use in an operational context.
If you can supply any of these, please contact us.
Any links shown in red are currently unavailable.
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© Crypto Museum. Created: Friday 08 November 2019. Last changed: Saturday, 09 November 2019 - 08:41 CET.