ngff-cardem: M.2 (NGFF) WWAN modem + SIM Card emulation board

This is a small carrier board for M.2 (NGFF) type cellular / WWAN modems with built-in SIMtrace2 (cardem, trace, ccid) support.

It allows you to insert a M.2 modem from any vendor, and it will provide you with:

  • microUSB-B (3.0) socket for connection to a USB Host (like your PC/Laptop or Embedded System)
  • DC input for power supply (USB supply usually insufficient for current peaks of a modem)
  • 1x SIM card slot for a 2FF-sized SIM, USIM or RUIM cards (dual-SIM)
  • built-in SIMtrace2 support for all of its modes
    • cardem: emulate a SIM card towards the modem (useful for remote sim, e.g. using osmo-remsim)
    • trace: trace the communication between physical SIM card and modem
    • reader: access the physical SIM card slot as a CCID reader from the host (firmware not implemetned yet)
    • mitm: perform man-in-the-middle between physical SIM card slot and modem (firmwre not implemented yet)


Machine produced v2 PCBA


First manually assembled v1 prototype


Design Files, Schematics, Component Placement

git repository

The most recent design files can be found in the ngff-cardem directory of the osmo-small-hardware git repository. See

PNG renderings of Schematics

schematic v2 (1/3)

(GND on OsmoSer connector is missing here, but not in current PCBA's version. Img needs to get updated.)

schematic v2 (2/3)

schematic v2 (3/3)

Where to buy

Open Source Hardware

The general idea of Open Hardware projects is that anyone is allowed to build the design. So feel free to take the design files and build it yourself, either modified or unmodified. Please make sure you always
  • attribute the original author (Attribution)
  • release any changes to the design files under the same terms (Share Alike)

Fully assembled kits for purchase

If you would like to buy a fully-assembled version of this board, including all required accessories, it can be ordered from the sysmocom webshop

Further reading

Commercial Support

Commercial support as well as development, system integration and training services for this project are available from sysmocom

Files (9)
ngff-cardem_schema.pdf View ngff-cardem_schema.pdf 90.1 KB ngff-cardem v1 schematics laforge, 09/25/2021 10:30 AM
ngff-cardem_placement.pdf View ngff-cardem_placement.pdf 46.2 KB ngff-cardem v1 component placement laforge, 09/25/2021 10:31 AM
ngff-cardem_p1_mr.jpg View ngff-cardem_p1_mr.jpg 263 KB picture of first assembled prototype laforge, 09/25/2021 10:32 AM
ngff-cardem.sch.pdf View ngff-cardem.sch.pdf 89.9 KB ngff-cardem v2 schematics laforge, 03/24/2022 02:29 PM
ngff-cardem.brd.pdf View ngff-cardem.brd.pdf 50 KB ngff-cardem v2 component placement laforge, 03/24/2022 02:29 PM
20220324_150653.jpg View 20220324_150653.jpg 422 KB ngff-cardem v2 picture laforge, 03/24/2022 02:30 PM
ngff-cardem.sch1.png View ngff-cardem.sch1.png 569 KB schematic v2 (1/3) laforge, 03/24/2022 02:34 PM
ngff-cardem.sch2.png View ngff-cardem.sch2.png 795 KB schematic v2 (2/3) laforge, 03/24/2022 02:34 PM
ngff-cardem.sch3.png View ngff-cardem.sch3.png 502 KB schematic v2 (3/3) laforge, 03/24/2022 02:34 PM

Updated by mschramm about 1 month ago ยท 9 revisions

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