Nevo Deep →
Credit card audio recorder
Nevo FX is a high-performance ultra low-power miniature digital
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.
A regular credit card reader is not suitable for the Nevo FX.
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.
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
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.
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.
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
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.
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.
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
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).
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.
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
➤ More about the Nevo Deep
DeviceCredit card sized audio recorder
PurposeCovert recording of conversations
Form factorCredit card
MicrophoneInvenSense ICS-43434 (built-in) 1
Dynamic range87 dB
Response60 - 15000 Hz (- 3dB)
Noise supp.-75 dBFS
Sampling rate8, 16 or 24 kHz
Resolution16- or 24-bit
Compression4-bit ADPCM (optional), 2 16-bit PCM, 24-bit PCM
Signature1024 bit RSA
Standby time135 hours 3
Recording12 - 74 hours
Capacity150 hours (ADPCM, 8 kHz) subject to 2 GB limit
Schedules5 (for scheduled recording)
RTCPowered by main battery
InterfaceUSB 2.0, USB 3.0
Power2.2 - 5.5V DC (from USB port)
CompatibilityWindows 7 - 10
Temperature-10°C to +40°C
Dimensions85.6 × 54.0 × 1.6 mm
PriceNevo FX: EUR 1150 (2017) 
Nevo FX Radio: EUR 1500 (2017) 
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].
Lossy compression which shrinks 16-bit files approx. 4 times.
In Voice Activated Mode (VAS).
- Kinetis K26, MKL26Z128VFT4 (M26M 7VFT)
Freescale/NXP, KL26P64M48SF5, Rev. 5, August 2014.
- 8Gb NAND Flash Memory, S34ML08G1
Spansion, Rev. 06, 1 April 2014.
- TPS62743 (TPS743) 300 mA High Efficiency Buck Converter
Texas Instruments, SLVSCQ0B, June 2015 (Rev. March 2021).
- ICS-43434 digital MEMS microphone
InvenSense/TDK, DS-000069, Rev. 1.1, 3 June 2016.
- CC1101, Low-Power Sub-1GHz RF Transceiver
Texas Instruments, SWRS0611, 2023.
➤ CC1101 Silicon Errata
- Kinetis K03, MKL03Z8VFG4 (M3T4 AFGV)
Freescale/NXP, KL03P24M48SF0, Rev. 5.1, August 2017.
- Anonymous, Gedion Nevo FX - THANKS !
Crypto Museum, May 2023.
- Catalog 2017, Special audio and GPS tracking devices
- Gedion, Pricelist 2017
August 2017, valid until 1 November 2017.
- Wikipedia, RSA (cryptosystem)
Visited 6 June 2023.
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© Crypto Museum. Created: Saturday 31 December 2022. Last changed: Monday, 19 June 2023 - 07:23 CET.