Click for homepage
← Hagelin
Voice
  
Hagelin CRM-008   CRYPTOCOM
Secure Voice Crypto Unit - HC-230/HC-235

CRM-008 is a Frequency and Time Domain Voice Scrambler (F/T), developed in the mid-1970s by Crypto AG (Hagelin) in Zug (Switzerland). The device was part of the CRYPTOCOM family of secure voice equipment, and was available for the civil market (HC-230) as well as for military customers (HC-235). Being a voice scrambler however, it was far less secure than anticipated.

The CRM-008 is suitable for direct connection to a telephone line, but can also be used 'over the air' by connecting it to an HF or VHF radio.

As low quality telephone lines and narrow band HF and VHF radio channels are generally not suitable for real digital signals, the CRM-008 uses a combination of frequency domain and time domain scrambling, which was — in the company's own words — unique in the business. This way, the characteristics of human speech are maintained in the transmitted signal, whilst the speech itself has become unintelligible [2].
  

The HC-230 and HC-235 were introduced in 1975 and were used in a number of countries well into the 1990s, in particular in South America. The devices were succeeded in the 1990s by the smaller HC-265 series. Being a member of the CRYPTOCOM family, the HC-265 was backwards compatible with the earlier HC-230/HC-235 (CRM-008). The HC-265 in turn, was succeeded in the 2000s by the even smaller and more versatile HC-2650 MultiCom series. Although MultiCom devices were primarily intended for securing data networks, they were also capable of securing speech by using advanced voice encryption, while maintaining backwards HC-265 compatibility.

More information will be added to this page as and when it becomes available.

CRM-008 main unit Main unit with keyboard visible Front panel seen from the left Front panel Front panel Front panel Keyboard Connectors and erase button
A
×
A
1 / 8
CRM-008 main unit
A
2 / 8
Main unit with keyboard visible
A
3 / 8
Front panel seen from the left
A
4 / 8
Front panel
A
5 / 8
Front panel
A
6 / 8
Front panel
A
7 / 8
Keyboard
A
8 / 8
Connectors and erase button

Models
  • CRM-008-001
    Mobile version powered by 10 to 30V DC and connected with a 4-wire audio interface. The device featured here is of this type.

  • CRM-008-007
    Desktop version with built-in AC power supply unit and telephone adapter circuitry for connection to standard 2-wire PSTN lines. This unit is higher than the mobile version.
Accessories
The following accessories and peripherals are available for the CRM-008:

ATF-114 Crypto phone
When using the CRM-008 over a PSTN telephone line, this special crypto phone had to be used instead of a standard phone.

The phone shown here is in fact a standard telephone unit that is modified for crypto use. It has extra switches and and a red light to show that the connection is secure. The crypto phone has an 8-way LEMO plug that should be connected to the phone socket of the CRM-008.
  

ATF-109 Telephone break-out box
In order to connect the CRM-008 to a telephone line, this small break-out box was used. It has two sets of banana-sockets that are used to connect to a standard (PSTN) telephone line and (optionally) to a telephone.

A fixed cable with a 10-way LEMO plug is used to connect the break-out box to the DATA socket of the CRM-008.
  

ARA-100-001 Radio Interface/Speaker Unit
The CRM-008 can also be used over radio. In that case, a radio interface is used instead of the telephone break-out box. The Radio Interface has a 10-way LEMO plug that connects to the DATA socket of the CRM-008.

The radio is connected to the rear of this unit, by means of two fixed wires (which are missing from the unit shown here).
  

ARA-100-002 Radio Interface
This unit is simular the the ARA-100-001 (shown above) but is missing the internal speaker. Instead it has a socket for headphones. A fixed cable with a 10-way LEMO plug is used to connect it to the DATA-socket of the CRM-008.

Furthermore, the radio interface has two short cables for connection to a military radio set. Both cables have a 13-way military BENDEX plug, one male, and one female.
  

Handset
When using the CRM-008 over a radio link, this military-grade handset should be connected to the phone socket of the CRM-008, by means of an 8-way LEMO plug (just like the ATF-114 crypto phone).   

PSM-106 Power Supply Unit
The CRM-008 can be connected to just any DC power supply with a voltage between 12 and 30 Volt. The one supplied with the unit is shown here. At present it is not known exactly how it connected to the CRM-008, as the DC power cable is missing.   

Crypto-prepaired telephone Close-up of crypto phone Telephone break-out box Radio interface Speaker Unit Handset Handset Power Supply Unit
B
×
B
1 / 8
Crypto-prepaired telephone
B
2 / 8
Close-up of crypto phone
B
3 / 8
Telephone break-out box
B
4 / 8
Radio interface
B
5 / 8
Speaker Unit
B
6 / 8
Handset
B
7 / 8
Handset
B
8 / 8
Power Supply Unit

Block diagram
Although the CRM-008 operates on analogue (speech) signals, the internal processing takes place in the digital domain. After the signal has been processed, it is converted back into an analogue signal, so that it can be transmitted of a standard narrow-band (radio) channnel.


The input audio signal is first split into two frequency bands with filters A and B. This filters have a center frequency of 1600 Hz with 5 selectable offsets (-300, -150, 0, 150 or 300 Hz). The two signals are then digitized and stored in separate buffers where they are further processed. In between the two frequency bands is a 1600 Hz pilot tone that controls the synchronization between transmitter and receiver and also controls the built-in Automatic Gain Control (AGC).


In the buffers, each segment of 320 ms is divided into 8 individual sections of 40 ms each. The 8 sections of the A-channel are then mixed with the 8 sections of the B-channel in a pseudo-random fashion that changes every 320 ms, under control of the built-in digital key generator.


Finally, the scrambled data sections are converted back to analogue signals in two D-A converters and mixed together in filters C and D. As the output signal still contains the properties of an analogue audio signal, it can be transmitted on narrow-band channels without problems. At the time, frequency/time domain scrambling (F/T) was considered to be safe from professional eavesdropping. Using modern correlation techniques however, the system is easily defeated without recovering the actual key. F/T scrambling should be regarded as extremely unsecure.


References
  1. Crypto AG, Crypto Magazine 2009, number 1.
    Retrieved August 2009. p. 12: Crypto AG's family tree.

  2. Crypto AG, CRM-008 Short Form Description
    Date unknown.

  3. Crypto AG, CRM-008 Short Form Instructions
    Date unknown.

  4. Crypto AG, ARA-100-102 Radio Interface Adapter
    Operating Instructions (English). January 1984.
Further information
Any links shown in red are currently unavailable. If you like the information on this website, why not make a donation?
Crypto Museum. Created: Monday 24 August 2009. Last changed: Saturday, 24 February 2018 - 10:15 CET.
Click for homepage