Relationship between PAF and COM ports
What is relationship between Pen Access Framework (PAF) and COM port names?
Here is how PAF works with COM ports:
- PAF enumerates all USB devices
- We receive list of strings in the format of "USB\\VID_2101&PID_8501&REV_0605"
- Later, the PAF selects strings that match PID and VID of pens ( "VID_1E61" )
- The resulting list will only contain pens
- Then for each pen in the list we get COM port name from the registry
- We open received ports. We don't change port names. We only configure timeouts and discard port buffers.
Also we don't do anything with ports that don't correspond to the pen.
Windows registry contains information about all com ports and their name. Information about Windows USB device path can be found here: http://community.silabs.com/t5/Interface-Knowledge-Base/Windows-USB-Device-Path/ta-p/114059