Attached is a simple sample that reads from COM ports by interoperating with
mscoredll.dll on the PocketPC using the Smart Device Extensions.
The sample is not finished, but it is functioning.

I developed this sample to communicate with a GPS flash card, however this
sample should work with *any* COM device. This particular sample supports
changing the Baudrate from the UI, but it would be quick to add support for
altering any of the (Device Control Block) DCB values.

the code requires 5 API calls:
CreateFile, SetCommState, GetCommState, ReadFile, and CloseHandle

The trick to get it working on the Compact Framework was using the correct
schema for the DCB structure that needs to be passed in to the GetCommState
and SetCommState calls. I originally tried to use the schema that is used
with Windows and quickly found that it did not work. I later learned the the
CE version differs from that of Windows.


To find out more about working with CE and COM Ports see MSDN's article
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wceseril/htm/cmconProgrammingSerialConnections.asp

Hope this is useful.

Regards,
-Hans Hugli