The GPS Dongle has ID_VENDOR_FROM_DATABASE Prolific Technology inc
so we loop through the attached usb-serial devices with for DEV in /dev/ttyUSB*;
for each of them we ask info about them do udevadm info -q env -n $DEV /dev/ttyUSB | grep -w 'DEVNAME\|ID_VENDOR_FROM_DATABASE' ; done
for DEV in /dev/ttyUSB*; do udevadm info -q env -n $DEV /dev/ttyUSB | grep -w 'DEVNAME\|ID_VENDOR_FROM_DATABASE' ; done
Giving an output of :
DEVNAME=/dev/ttyUSB0
ID_VENDOR_FROM_DATABASE=Future Technology Devices International, Ltd
DEVNAME=/dev/ttyUSB1
ID_VENDOR_FROM_DATABASE=Prolific Technology, Inc.
Now we know which /dev/ttyUSB? is connected to which manufacturers device.