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Nagra CBR
Miniature covert body recorder

The CBR, or Covert Body Recorder, is a hi-end electronic body wearable miniature audio recorder, developed by Nagravision SA (now: Nagra Audio) in Cheseaux-sur-Lausanne (Switzerland). It was introduced in 2007 [1] as the successor to the tape-base Junior Body Recorder (JBR). The device is intended for covert recordings and espionage and is mainly used by intelligence agencies and the law enforcement community. Therefore, its specifications were kept secret by the manufacturer.
The bare CBR itself measures just 55 x 60 x 12 mm and is housed in a typical Nagra eloxed aluminium enclosure. It it powered by two AAA-size batteries that are contained in an external battery holder that is attached to the bottom of the CBR by means of a slide-on lock. Both the device and the battery are shown on the right.

The audio quality of the CBR is unsurpassed. The device can record nearly 3 hours of audio from two miniature microphones (stereo) in linear Pulse-Coded Modulation (PCM) with a sampling rate between 32 and 48 kHz (typically 44.1 kHz).
Nagra CBR with external batteries

When using data compression, the built-in 2 GB memory can hold over 69 hours of sound, whilst the audio quality, remains excellent. Depending on the type of batteries, the device can record continuously for 6 to 10 hours. For unattended recording, the device can be voice actuated (VOX).

The CBR comes with a software package that runs on MicrosoftTM compatible PCs. It allows all aspects of the CBR to be configured, such as the file format, the amplifier levels, the sound compressor and the real time clock. If a recorded conversation has to be submitted for evidence in a trial, an SHA-1 signature can be added to ensure that the file has not been tampered with.

Development of the CBR started around 2004, but the device wasn't released until 2007 [1]. It was intended as a replacement for the Junior Body Recorder (JBR), the last generation of tape-based body wearable miniature covert recorders that was developed in cooperation with the FBI. The CBR was still available from Nagra in 2014, but is not listed in the normal catalogue. It is for the law enforcement and intelligence community only, and costs approx. EUR 2040 (excl. VAT). Apart from the CBR, Nagra also offers the CCR, which is a covert recorder in credit card format.
Storage case Contents of the storage case The bare Nagra CBR Nagra CBR and battery holder Battery holder with two AAA-cells Nagra CBR with external batteries Microphones connected to the CBR Nagra CBR with connected peripherals ready for use

The image below shows a complete covert recording setup with the Nagra CBR at the heart. The unit is powered by a small battery pack (with two AAA-cells) that is attached at the bottom. At the left is the plastic remote start/stop slide-switch. At the right are the two miniature microphones.

Like its predecessor, the Nagra JBR, the CBR has virtually no controls, except for the START/STOP slide-switch. This was done to avoid operator errors and tampering. All further settings of the CBR are under software control and have to be adjusted by means of a PC prior to its assignment.

Recording can be started and stopped either with the red slide-switch on the side of the recorder, or with the separate remote control unit. The exact function of each of these two switches can be determined in software. It is also possible to use one switch for playback. At the rear is a small red LED that is used as an activity indicator. When recording, it flashes quickly. The LED can be concealed by a nifty mechanical cover, so that it won't give itself away when used in the dark.

Initially the 90° 3.5 mm jack plugs and the remote control unit were custom-made Nagra parts, milled out of a solid block of aluminium. Later, the aluminium parts were replaced by plastic ones. This might have been done to reduce the overall cost of the unit, but could also be done because plastic is softer than metal and therefore causes less damage to the operator's clothing.
Nagra CBR with connected peripherals ready for use Nagra CBR and two sub-miniature microphones Set of two sub-miniature microphones Close-up of the microphone connector Close-up of the ultra-miniature microphone Start recording a conversation Close-up of the activity indicator Concealed activity indicator

Contents of the storage case

The CBR comes in a small black plastic transport case, with cut-outs in the foam for the device and the various accessories. Two subminiature microphones are supplied, each with 1.5 metres of teflon coaxial cable, ending in a single 90° Nagra 3.5 mm stereo jack that should be inserted into the socket at the top. The jack plug is secured by means of a locking bolt. In the same way, the (optional) remote control unit can be connected and locked to the left side of the CBR.
Storage case Contents of the storage case The bare Nagra CBR Set of two sub-miniature microphones Remote control unit (start/stop) External power lead USB cable Software on mini-CD

Power supply
The Nagra CBR is powered by two AAA-size batteries that should be installed in the separate battery unit shown below. The battery holder can be opened at the side by unlocking the bright blue cover. The orientation of the batteries is printed on the cover of the battery holder.
The image on the right shows the CB-BB1 battery holder with one of the sides taken off and one AAA-size battery half-way inserted. The two batteries should provide enough energy for continuous recording of up to 6 to 10 hours.

If longer recording times are necessary, for example when using the device in unattended voice-operated mode (VOX), the separate CB-EDC external DC adapter can be installed in place of the battery holder. It has the same form factor as the battery holder and allows any DC source between 8 and 16 Volt to be used.
Battery holder with two AAA-cells

The external DC adapter has a socket for a 2-pin LEMO connector at its side and should be used with the supplied extension cable and virtually any external DC source, such as the battery of a car. Using this feature in combination with voice-operated recording (VOX) and data compression, the Nagra CBR can record over 69 hours of sound over a period of several days.
Nagra CBR and battery holder Case lock at the side of the battery holder Battery holder with two AAA-cells Battery holder with two AAA-cells Closing the battery holder Securing the locking bolt LEMO socket at the side of the external DC power adapter Nagra CBR powered by an external DC source

Play-back on a PC
Like its predecessor the Nagra JBR, the Nagra CBR is a recording-only device, which means that an external unit is needed to play back a recorded conversation. Whilst this was done in the past with external tape players, an ordinary PC can now be used to play back the CBR's recordings.
The CBR is connected to the PC via a common USB interface using the supplied cable. Supplied with the kit is a mini-CD with the necessary software that runs under Microsoft WindowsTM. This can be installed on a native PC or on an alternative platform using PC emulation.

Once the software is installed, the PC can be used as a fully fledged playback system, with full control over the various samples and the date and time they were recorded. Samples can be transcribed and fragments can be exported for use elsewhere, e.g. for further investigation.
Software on mini-CD

The software is also used for setting up the device for the required task. The function of the ON/OFF switch on the body of the CBR and the function of the external remote control switch can both be defined from the software. Furthermore, the software is used to set date and time of the internal real-time clock, select between Linear PCM and compressed audio, set the recording levels, enable voice-operated recording, select between internal and external microphones, etc.
  • CB-BB1
    Battery holder
  • CB-RC1
    Remote control unit
  • CB-EDC
    External DC Adapter
Technical specifications
  • Dimensions
    60 x 55 x 18 mm
  • Weight
    86 g (110 g including 2 AAA-size batteries)
  • Running time
    6 to 10 hours
  • Internal memory
    2 GB
  • File and control Interface
  • Uncompressed recording
    > 3 hours in stereo at CD quality (PCM Linear)
  • Compressed recording
    > 69 hours
  • Time logging
    Built-in Real-Time Clock (RTC)
  • Digital signature
  1. Nagra Audio, Machine History
    Retrieved July 2014. 1

  2. Nagravision SA, Nagra CBR Manual
    Part number 2027 001 150. Version 4 january 2008. 26 pages.

  1. The Nagra CBR used to be listed in the Machine History overview on Nagra's website until July 2014. In the current Product History overview it is no longer listed. The original list can be found here.

Further information

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Crypto Museum. Created: Friday 25 July 2014. Last changed: Friday, 02 December 2016 - 08:05 CET.
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