A device has a Vendor ID (VID) and a Product ID (PID). For example, the following is output from lsusb:

Bus 002 Device 013: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

0a12 is the VID for CSR, and 0001 is CSR's PID for "Bluetooth Dongle (HCI mode)." You can find a list at:

http://www.linux-usb.org/usb.ids

Microchip has paid USB Forum for its VID 04d8. If you build a USB peripheral with one of their microcontrollers, you can ask Microchip to allocate you a PID (since they have 64K of these), and let you use their VID:

http://ww1.microchip.com/downloads/en/DeviceDoc/APPLICATION%...