How to find out which USB-RS232 device is on which tty?

Question

I have two different USB devices based on the same USB-RS232 chips. When I plug those in the USB they are mounted to /dev/ttyUSB0...3

My problem is how, inside a script,

Answer 1

Find more info using sysfs:

$ ls /sys/bus/usb-serial/devices/ -ltrah

lrwxrwxrwx 1 root root 0 2012-02-07 22:17 ttyUSB0 -> ../../../devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0

$ ls -ltrad /sys//devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0
drwxr-xr-x 4 root root 0 2012-02-07 22:17 /sys//devices/pci0000:00/0000:00:0f.4/usb2/2-2/2-2:1.0/ttyUSB0

$ ls -ltrad /dev/ttyUSB0 
crw-rw---- 1 root dialout 188, 0 2012-02-01 00:17 /dev/ttyUSB0

Of course, the linked devices/... node contains a lot of information

Adding information based on the OP's comment:

The device number keeps growing if devices are removed/inserted. lsusb -t can be used to correlate the device numbers with usb bus/port.

Then, 'lsusb -d devID' can determine what device is on which port. Finally 'ls /sys/bus/usb-serial/devices/ -ltrah' will list (by bus/port) where it was mounted.

Not very convenient, but it 'works'