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Nevo FX
Credit card audio recorder

Nevo FX is a high-performance ultra low-power miniature digital audio recorder in the shape of a plastic credit card, developed around 2015 by Gedion Ltd. in Vilnius (Lithuania) as part of its covert surveillance portfolio. Intended for the law enforcement and intelligence community, the recorded data is tagged with a 1024-bit RSA key, so that it can be used as legal evidence in a criminal investigation. A remote controllable variant of Nevo FX is available as the Nevo FX Radio. A smaller — embeddable — version with remote control capability is available as the Nevo Deep.

The device is just 1.5 mm thick and has a very sensitive microphone that behaves well under difficult acoustic conditions like wind and noisy environments. It has a 2 GB memory that can hold up to 150 hours of audio data. Recordings can be scheduled or voice activated. In addition, the radio variant can be remote controlled.

It is supplied with a USB cradle which mates with the gold-plated contact pads on the credit card recorder. 1 The front and back of the credit card recorder can be printed with a custom design, to resemble a bank card or an identification badge.

The design is similar, but not identical, to the Nagra CCR, a high-end Credit Card Recorder (CCR) developed by Nagra Audio in Switzerland for use by law enforcement and intelligence agencies. The specifications of the Nevo FX are very similar. 2 Nevo FX was available in 2017 from various resellers for EUR 1150 excluding VAT. The remote controlled version was available for EUR 1500.

  1. A regular credit card reader is not suitable for the Nevo FX.
  2. Nevo FX is also sold by other resellers under a variety of brand names, and it is not always clear whether it's the same or or a similar product. Examples are Cobra DVR-24, REC-CARD and GTG-PRO.

Plstic storage case with Nevo FX
Nevo FX in storage case
Nevo FX credit card audio recorder
USB cradle with Nevo FX
Nevo FX credit card audio recorder with accessories
Nevo FX compared to the Nevo Deep
Nevo FX with Nevo Deep in front
Small microphone hole
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Plstic storage case with Nevo FX
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Nevo FX in storage case
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Nevo FX credit card audio recorder
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USB cradle with Nevo FX
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Nevo FX credit card audio recorder with accessories
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Nevo FX compared to the Nevo Deep
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Nevo FX with Nevo Deep in front
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Small microphone hole

The image below shows the exterior of the Nevo FX. The device resembles a regular credit card and is just 1.5 mm thick. The only external features that are visible, are the contact pads — used for connection to the USB port of a Windows PC — and a tiny hole behind which the digital MEMS microphone is located. Furthermore, a touch/slide interface is hidden along the upper edge of the card. Move the mouse pointer over the image to reveal the building blocks of the Nevo FX.

In the image above, the microphone port is easily visible as the surrounding area is white. For a better concealment it would be more appropriate to use a dark background, or to print black text in this area. This would make the pinhole microphone port virtually undetectable.

  • Nevo FX
    This is the standard version of the credit card audio recorder. It does not offer remote control facilities, but can make scheduled and voice activated recordings. In addition, it can be controlled manually via a touch interface. The device featured here is of this type.

  • Nevo FX Radio
    This is a more advanced version of the device with a built-in radio transceiver to allow remote control from a distance up to 15 metres. This version comes with a remote control unit, disguised as a car key fob. The design is similar (but not identical) to the Nevo Deep audio recoder, albeit with a larger battery.

Storage case
Nevo credit card audio recorder
USB cradle
Optional remote control unit
Nevo Manager for Windows 7-10
Storage case
Nevo FZ is supplied in a compact plastic storage case, such as the one shown in the image on the right. Inside the case are a USB cradle, a remote control unit (only with the Nevo FX Radio), a memory stick with the Nevo Manager software, and the Nevo FX credit card recorder itself.

The image on the right shows a complete kit with a credit card recorder that is printed with the Nike logo. The remote control unit (i.e. the car key fob) is missing from the kit shown here.


Recorder   Nevo FX
The recorder has the shape of a regular credit or bank card, or an ID badge. The contact pads — normally intended for communication with a banking terminal — are used here for the USB interface. The actual recorder takes up the left 1/3rd of the card, whilst the remaining space is used for the rechargeable LiPo battery.

The device shown here is printed with the Nike logo, but in practice it would often be printed with a custom design of a credit card or an ID badge, so that it could be worn in plain sight.


USB cradle
A special cradle is provided for connecting the credit card recorder to the USB port of a regular Windows PC. There are no electronics inside the cradle; just four slide contacts that mate with the gold-plated contacts at the card's surface.

Note that a regular USB card reader is not suitable for connecting the Nevo FX to the computer.


Remote control unit   option
The remote control unit is concealed as a car key fob and is only available with the Nevo FX Radio version. It works on a channel in the 868 MHz ISM band. When enabled, it allows a recording to be started and stopped remotely.

There are three buttons: (1) on, (2) off and (3) function. Button (1) and (2) are used to turn the device ON and OFF. Button (3) allows the status of the device to be checked remotely. It can also be used to turn on the LED on the device, so that the USB contacts can be found more easily.


Software   Nevo Manager
The device can be configured via a regular PC running Windows 7 to 10, using the proprietary Nevo Manager software that is supplied with the kit. It controls the recording schedule, the use of the remote control unit and the voice activiation system (VAS). It also allows the digitally signed audio recordings to be downloaded to the PC.

The Nevo Manager software is protected with an installation key and the Nevo FX uses a proprietary storage format.

Plstic storage case with Nevo FX
Nevo FX in storage case
Nevo FX Radio in storage case
USB cradle with Nevo FX
Remote control unit (car key fob)
USB memory stick with software
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Plstic storage case with Nevo FX
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Nevo FX in storage case
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Nevo FX Radio in storage case
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USB cradle with Nevo FX
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Remote control unit (car key fob)
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USB memory stick with software

The interior of the Nevo FX cannot be exposed without damaging the plastic layers of the (fake) credit card. We therefore decided not to take the device apart, but to have it x-rayed instead. The image below shows the complete credit card as seen from the front (i.e. the side with the contact pads), which appears to be the bottom of an ultra thin PCB. This means that we are looking at the bottom of the components here. The electronics are at the left. The large grey area at the right is the rechargeable LiPo battery. At the top right are the capacitive contacts of the touch interface.

Note that in the x-ray, the LiPo battery appears to have only one terminal. Luckily, this is not the case. As the (+) terminal is made of aluminium foil, it is barely visible in the x-ray. The touch interface is a bit of a surprise, as it is not mentioned in the manual of the Nevo FX Radio (which is the only Nevo FX manual we have). It is mentioned however, in the product leaflet of the Nevo FX, as distributed by reseller Law Abiding Technology (LAT) in Delhi (India) [B]. We will now zoom in on the electronics section that occupy the leftmost 1/3rd of the available space.

From the x-ray it is impossible to determine the types of the various parts, but there are a few educated guesses we can make, based on the information that can be gleaned from the USB port and the tear-down of a similar Gedion product: the Nevo Deep. The Nevo FX is built around a single microcontroller, which appears to be identical to the master controller of the Nevo Deep: a Freescale Kinetis K26 [a]. At the left are two flash devices with a capacity of 1GB and an 8-bit interface each. It is very likely that these are two S34ML08G1 devices made by Spansion [b].

At the top right is the ICS-43434 digital MEMS microphone made by InvenSense (now: TDK). 1 This microphone directly produces a digital data stream through its I2S interface, which is readily accepted by the KL26 microcontroller. This microcontroller also has a built-in USB interface, which is directly connected to the gold-plated contact pads of the 'credit card'. A miniature Texas Instruments TPS62743 high-efficiency step-down converter is used to convert the +5V power supply from the USB port to +2.2V needed by the microcontroller (and for charging the battery).

  1. In the manual [A], the microphone is listed as a Knowles ICS-43434, but we believe this to be a mistake, as the ICS-43434 is made by InvenSense (now: TDK) [d].

Comparison with Nevo Deep
The circuit of the Nevo FX is much simpler than that of the Nevo Deep, basically because the latter also has a radio interface. It is believed though, that the basic recorder of the Nevo Deep is nearly identical to the Nevo FX, as the same microcontroller and flash memory devices are used.

The image on the right shows a Nevo Deep bare PCB on top of the Nevo FX credit card recorder. Although Nevo Deep is smaller than Nevo FX, the actual electronics section is larger as it holds more components. To save space, a relatively small LiPo battery is used with the Nevo Deep.

With the Nevo FX, the outer dimensions are less of an issue, as it is bound to the size of a credit card. This means that a much larger LiPo battery can be fitted, which improves the recording time of the device. It can record continuously up to 74 hrs, compared to just 5.5 hours on Nevo Deep.

From a software point of view, the two devices are identical. They are both supported by the same Nevo Manager software and offer the same functionality with respect to scheduled recording. Nevo Deep is ideal for situations where the recorder must be hidden inside a concealment and space is a serious constraint, such as in the spine or the cover of a book. In situations where concealment isn't mandatory however, such as with an ID badge, the Nevo FX would be the perfect choice as it can be worn in plain sight and therefore offers a much better audio quality.

Nevo FX Radio
The above x-ray images show the contents of the Nevo FX, which is different from the Nevo FX Radio. It is likely that the latter is more similar to the Nevo Deep as it offers remote control. It is likely that Nevo FX Radio contains a CC1101 radio transceiver, operating in the 868 MHz band [e]. In that case it is also likely that a second Freescale microcontroller — probably a Kinetis K03 variant — is present for power management [f].

 More about the Nevo Deep

X-ray of the complete credit card recorder
X-ray of the electronics only
Nevo FX compared to the Nevo Deep
Nevo FX compared to the Nevo Deep
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X-ray of the complete credit card recorder
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X-ray of the electronics only
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Nevo FX compared to the Nevo Deep
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Nevo FX compared to the Nevo Deep

  • Device
    Credit card sized audio recorder
  • Purpose
    Covert recording of conversations
  • Manufacturer
    Gedion Ltd.
  • Model
    Nevo FX
  • Year
  • Country
  • Form factor
    Smart card
  • Channels
  • Microphone
    InvenSense ICS-43434 (built-in) 1
  • Dynamic range
    87 dB
  • Sensitivity
    -26 dBFS
  • Response
    60 - 15000 Hz (- 3dB)
  • Noise supp.
    -75 dBFS
  • Memory
    2 GB
  • Format
  • Sampling rate
    8, 16 or 24 kHz
  • Resolution
    16- or 24-bit
  • Compression
    4-bit ADPCM (optional), 2 16-bit PCM, 24-bit PCM
  • Signature
    1024 bit RSA
  • Standby time
    135 hours 3
  • Recording
    12 - 74 hours
  • Capacity
    150 hours (ADPCM, 8 kHz) subject to 2 GB limit
  • Schedules
    5 (for scheduled recording)
  • RTC
    Powered by main battery
  • Interface
    USB 2.0, USB 3.0
  • Power
    2.2 - 5.5V DC (from USB port)
  • Software
    Nevo Manager
  • Compatibility
    Windows 7 - 10
  • Temperature
    -10°C to +40°C
  • Dimensions
    85.6 × 54.0 × 1.6 mm
  • Weight
    4 g
  • Price
    Nevo FX: EUR 1150 (2017) [3]
    Nevo FX Radio: EUR 1500 (2017) [3]
  1. In the manual [A], the microphone is listed as Knowles ICS-43434, but we believe this to be a mistake, as the ICS-43434 is made by InvenSense (now: TDK) [d].
  2. Lossy compression which shrinks 16-bit files approx. 4 times.
  3. In Voice Activated Mode (VAS).

  1. Kinetis K26, MKL26Z128VFT4 (M26M 7VFT)
    Freescale/NXP, KL26P64M48SF5, Rev. 5, August 2014.

  2. 8Gb NAND Flash Memory, S34ML08G1
    Spansion, Rev. 06, 1 April 2014.

  3. TPS62743 (TPS743) 300 mA High Efficiency Buck Converter
    Texas Instruments, SLVSCQ0B, June 2015 (Rev. March 2021).

  4. ICS-43434 digital MEMS microphone
    InvenSense/TDK, DS-000069, Rev. 1.1, 3 June 2016.

  5. CC1101, Low-Power Sub-1GHz RF Transceiver
    Texas Instruments, SWRS0611, 2023.
     CC1101 Silicon Errata

  6. Kinetis K03, MKL03Z8VFG4 (M3T4 AFGV)
    Freescale/NXP, KL03P24M48SF0, Rev. 5.1, August 2017.
  1. Nevo FX Radio - Operating instructions
    Gedion Ltd. Undated.

  2. Credit Card Audio Recorder - Leaflet
    Law Abiding Technology, Undated.
  1. Anonymous, Gedion Nevo FX - THANKS !
    Crypto Museum, May 2023.

  2. Catalog 2017, Special audio and GPS tracking devices
    Gedion, 2017.

  3. Gedion, Pricelist 2017
    August 2017, valid until 1 November 2017.

  4. Wikipedia, RSA (cryptosystem)
    Visited 6 June 2023.
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Crypto Museum. Created: Saturday 31 December 2022. Last changed: Wednesday, 08 May 2024 - 13:04 CET.
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