There are plenty of cellular modems on the market in the mPCIe form
factor.
Playing with such modems is reasonably easy, you can simply insert them
in a mPCIe slot of a laptop or an embedded device (soekris, pc-engines
or the like).
However, many of those modems actually export interesting signals like
digital PCM audio or UART ports on some of the mPCIe pins, both in
standard and in non-standard ways. Those signals are inaccessible in
those embedded devices or in your laptop.
So I built a small break-out board which performs the basic function of
exposing the mPCIe USB signals on a USB mini-B socket, providing power
supply to the mPCIe modem, offering a SIM card slot at the bottom, and
exposing all additional pins of the mPCIe header on a standard 2.54mm
pitch header for further experimentation.
The design of the board (including schematics and PCB layout design
files) is available as open hardware under CC-BY-SA license terms. For
more information see
SOCIAL SHARE CARD GENERATOR