The USB Serial Driver Layer

The /proc/tty/driver/usb-serial File

This file describes all of the currently plugged in USB serial devices.

usbserinfo:1.0 driver:v1.4
0: module:keyspan name:"Keyspan 1 port adapter" vendor:06cd product:0119
num_ports:1 port:1 path:usb-00:02.3-1
1: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:1 path:usb-00:02.2-1
2: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:2 path:usb-00:02.2-1
3: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:3 path:usb-00:02.2-1
4: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:4 path:usb-00:02.2-1
5: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:5 path:usb-00:02.2-1
6: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:6 path:usb-00:02.2-1
7: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:7 path:usb-00:02.2-1
8: module:io_edgeport name:"Edgeport 8 port adapter" vendor:1608
product:000f num_ports:8 port:8 path:usb-00:02.2-1

In this example, two different USB-to-serial devices are plugged in: a single-port Keyspan adapter and an eight-port Edgeport adapter. This file is useful in determining which minor number is assigned to which specific port and adapter. For more information on the individual fields of this file, see the drivers/usb/serial/usb-serial.c file.