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Hagelin CRM-008 (CRYPTOCOM)
Secure Voice Crypto Unit - HC-230/HC-235

The CRM-008 was part of the CRYPTOCOM family of secure voice units, developed by Crypto AG (Hagelin) in Switzerland in the mid-1970s. It was intended for civil use (HC-230) as well as for the military market (HC-235). It was introduced in 1975 and was used well into the 1990s.
 
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 fully digital signals, the CRM-008 uses a combination of frequency domain and time domain scrambling [2]; according to the company's description: unique in the business. This way, the characteristics of human speech are maintained in the transmitted signal, whilst the speech itself has become unintelligible.

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

The HC-230 family was replaced in the 1990s by the smaller HC-265 series. Being a member of the CRYPTOCOM family, the HC-265 was backwards compatible with previous units. The HC-265 itself was replaced in the 2000s by the even smaller and more versatile HC-2650 MultiCom. Although this unit is primarily intended for securing data networks, it features advanced voice encryption and is backwards compatible with the HC-265.
 
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

 
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.

Operation
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 is now classified as extremely unsafe.
 
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

 
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

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