GAPfiller GSM900 Design Files Released!

The hardware design files for the GAPfiller GSM900 have been released on  Github

  • Includes: OrCAD schematics, PADS PCB layout, Gerber files.
  • Coming soon: USRP FPGA firmware modifications, USRP Hardware Driver (UHD) and OpenBTS Transceiver modules for GAPfiller GSM900, technical documentation

The GAPfiller GSM900 is open-source hardware, released under the CERN Open Hardware License version 1.2.

January 2014 Update


Close-Haul Communications, Inc. is an open source wireless hardware company founded in 2009 by Robin Coxe and Tux the Polyester Penguin. Our tagline, Closing Gaps, Opening Access, captures our intention to design and build affordable, open wireless infrastructure hardware that enables people to create cellular networks outside the walled gardens of telecom monopolies. Close-Haul Communications is a charter member of the Open Source Hardware Association. Our first design, the GAPfiller GSM900, is intended as a prototyping platform for OpenBTS research and has been optimized for the GSM 900 band (GAP= GSM Access Point). The GAPfiller GSM900 is a mezzanine card compatible with the Ettus Research USRP series of software defined radio baseboards. Although not yet released commercially, the GAPfiller GSM900 board is open-source hardware covered under the CERN Open Hardware License, version 1.2.

The design files (OrCAD schematics, PADS PCB layout, Gerber files, and supporting documentation) were uploaded to Github on 7 January 2014. FPGA firmware and Linux driver modifications will be necessary to run OpenBTS or osmo-trx on the GAPfiller900. Stay tuned for more details.