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Picture of FCDEV3B board

We are proud to introduce our first FreeCalypso hardware product: a GSM mobile station development board. Our board features the same legendary TI Calypso GSM MS chipset that was used in commercial GSM/GPRS modems such as Openmoko's (our design is based on TI's Leonardo schematics and Openmoko's PCB layout), and functions as a standalone (or bare) GSM modem. The name of our board is FCDEV3B, which stands for FreeCalypso development board, triband.

We originally designed this board for our internal needs, to provide a proper platform for further development of our FreeCalypso software and firmware, but the product is a versatile GSM MS development board that can be used for all kinds of GSM learning and experimentation. The complete design files for our board are published, the Calypso chipset itself is also very well-documented, and ours is not the only software/firmware project that runs on the Calypso.

Hardware features


Compared to the mainstream commercial GSM modem kits for hobbyists and tinkerers and IoT/M2M applications and whatnot, our FreeCalypso GSM modem is unique in that it is explicitly designed to allow you to tinker with the inner workings of its firmware: you are explicitly encouraged to recompile our firmware from source and to flash your own fw builds into the modem, as well as to study our source, learn how it works, and make your own improvements which we never dreamt of. And if you totally dislike our firmware and wish to write your own completely from scratch instead, all hardware registers and functions are fully documented.

Compared to the ultra-cheap Motorola C1xx phones which are also based on the same Calypso chipset and which may thus seem no worse at first glance, our board is a fairly direct (by way of Openmoko) derivative of TI's Leonardo reference design, whereas Motorola's (really Compal's) hw design is considerably mutilated relative to the Leonardo baseline. Here are the serious shortcomings of Mot C1xx hardware:


Please read our user's manual, so you know exactly what you will be getting before you buy.


You can get one or more FCDEV3B boards in one of two ways:

  1. You can buy a single board off the stock shelf (i.e., a board that has already been produced and tested, and is known to be good) for $500 USD. This price includes the board itself, the screw-on GSM antenna and a Weidmuller 1716330000 connector for making your own power supply cable, but no other accessories. The following two accessories are available for $50 extra each:

    • An ultra-compact power adapter from universal AC mains to 3.6 VDC with 2.2 A current rating, needed to support GSM burst transmission;
    • An FT2232D USB adapter board and a set of jumper wires for connecting it to the two low-voltage UARTs on our FCDEV3B.

    No loudspeaker or microphone are included; if you need to exercise voice calls or Calypso DSP audio features, you will need to provide and connect your own loudspeaker and mic.

  2. You can order a batch of boards to be produced specifically for you, independent of our stock condition. The minimum order quantity with this option is 10 boards, but larger order quantities are strongly encouraged as the per-unit cost goes down with increasing order quantity. A custom quote is required (serious inquiries only, please), and you get to select the configuration for your boards:

    • RoHS or traditional SnPb solder;
    • Analog audio circuits on the board included or omitted;
    • The desired set of accessories beyond the boards themselves.

If you are interested in buying one or more FCDEV3B boards per either of the two options above, please email Mychaela.