Voice encryption handset
ORTHROS was a small leight-weight handset with built-in encryption and
decryption, developed by Philips Usfa in Eindhoven
(Netherlands) around 1987.
Being half-duplex, it was intended for use in combination with mobile VHF
radios. Unfortunately, it was never taken into production.
ORTHROS was an attempt by Philips Usfa
to produce equipment for civil applications, based on their extensive
experience in the military market and an
Using advanced in-house developed cryptographic algorithms, ORTHROS would
have posed a real threat to eavesdroppers on mobile radio channels .
The device measured 75 x 100 x 300 mm, which is roughly the size of a
telephone handset with a large 'blob' at the bottom.
It weighted 600 g and was available in either black or white.
It could be powered by the radio or by internal batteries.
Speech was processed by a digitally
controlled delta modulator (DCDN) before it was encrypted at 9,600 to
64,000 bits per second by the military-grade crypto unit,
making it suitable for VHF/FM radio with 25 kHz channel spacing .
The unit has 4 control buttons at the bottom and a push-to-talk (PTT) button
at its side. Above the 4 control buttons are 5 indicator lights. The first
three lights show which encryption key is selected. The upper left button is
used to select the required key. The upper right button is used to turn the
unit off. The device can be turned on by pressing either volume-up or
ORTHROS could hold up to 3 encryption keys, but at present it is
unclear how the keys were loaded into the device. Whenever security was
compromized, the keys could be destroyed by pressing 3 buttons simultaneously
(PTT, KEYSEL and volume-up). This is called: ZEROIZING.
The keys were also destroyed automatically, whenever the unit was opened
It was the aim of Philips Usfa to develop a family of secure voice
devices of which the radio version (ORTHROS) was planned to be
released first. The complete product was developed and a
full-colour leaflet was released,
but the unit was never taken into production.
This was partly due to the fact that the Dutch government didn't want
advanced cryptography to be available to the general public at the
time . As far as we know, there are no surviving ORTHROS units.
In Greek mythology, ORTHROS was the two-headed guard dog,
brother of the three-headed Cerberus. Orthros was charged by the giant
Eurution with guarding his purple herd.
As far as we know, there are no ORTHOS units left. The only item that
has surfaced in 2011, is the keyboard of this unit.
It is a plug-in unit with 4 PCB-mounted switches and 5 LEDs,
made by Fela Switch Panel in Switzerland. If you know a surviving ORTHOS
unit, please contact us.
The design of ORTHROS was based on the development of a military
encryption handset that was developed by Philips a year earlier .
Based on past experiencies with mobile voice encryption devices
like the Spendex 10,
Philips wanted to build the entire crypto device into the handset.
The old Spendex 10 was designed as a separate
encryption unit that was intended for the
RT-3600 radio, built by PTI in
Hilversum. Being the same size as the RT-3600 and being integrated
with the complete concept of the RT-3600, it was not very practical
on other types of radio.
By integrating the electronics into the handset, the encryption unit
could be used with virtually any type of (military) radio, simply by
connecting it to the 5-pin U-229 socket
that is present on nearly all radios. The image on the right shows
an artist impression of such a military handset.
This military handset was designed around 1986 and was initially intended
for use with the successor of the RT-3600,
the RT-4600, that was also being
developed by PTI in Hilversum. Unfortunately however, the design wasn't
finished when the radio was ready for release,
and a competing product was chosen instead.
As a result the project was cancelled and the product never saw the light
of day. Two attempts to release the handset as a commercial product, the
half-duplex ORTHOS (above) and the
full-duplex UP-2081 (below) also failed.
The UP-2081 was another attempt to use the technology developed for
the Military Handset
and the ORTHOS handset above. The UP-2081 was
developed in 1989 for full-duplex applications, such as ordinary
(domestic) telephone sets and the first generations of (analogue)
The UP-2081 was much smaller than the earlier ORTHROS and had a far more
elegant design, resembling a simple standard telephone handset of
the era. Most of the controls were located on the inside of the handset,
together with a 2-digit 7-segment LCD display. Two versions of the
UP-2081 were planned: one with 3 sets of up/down buttons and
one with a standard phone keypad.
The image on the right shows the version with the up/down buttons.
The display was probably intended for selection of the appropriate
crypto key. A picture of the other version
is available below. Apart from these case mock-ups, no actual
hardware was ever released.
- Philips Usfa stock photographs
Crypto Museum Photo Archive.
- Philips Usfa BV, ORTHROS mobile secure radio voice system
ORTHROS leaflet. 1987. Document number 9922/154/13041.
- Interview with a former Philips Usfa employee
Eindhoven, June 2011.
- Former Philips Usfa/Crypto employee, Military handset and UP-2081
Personal correspondence, February 2013.
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© Crypto Museum. Created: Tuesday 05 July 2011. Last changed: Friday, 22 July 2016 - 10:03 CET.