[Xastir] Interaction between radio and gpsd

[Liz]

I have uncovered a little 'gotcha' which was one of the causes of
fragility of my mobile xastir setup.
The writers of the udev rules for gpsd noted that many gps devices
actually used a pl2303 serial to usb chip, and decided to write them
into the udev rules at /lib/udev/rules.d/60-gpsd.rules

=================================
# udev rules for gpsd
#
# This file is Copyright (c) 2010 by the GPSD project
# BSD terms apply: see the file COPYING in the distribution root for
details. 
#
# GPSes don't have their own USB device class.  They're serial-over-USB
# devices, so what you see is actually the ID of the serial-over-USB
chip. 
# Fortunately, just two of these account for over 80% of
consumer-grade 
# GPS sensors.  The gpsd.hotplug wrapper script will tell a running gpsd 
# that it should look at the device that just went active, because it 
# might be a GPS.
#
===============================

I found this gem because I wanted to set my /dev/ttyACMx device to
autostart on gpsd, and was then able to comment out all the pl2303
entries because I have a pl2303 serial to usb device connecting my
radio to the computer.