Today I installed TP-Link TL-WN722N usb wireless adapter on Linux Debian system. Linux does not recognize this adapter by default so you need to install it manually.
Here is my method:
1. Open sources.list with sudo:
2. Paste this deb command in the end of file:
# Debian 8 "Jessie" deb http://httpredir.debian.org/debian/ jessie main contrib non-free
3. Update the list of available packages and install the firmware-atheros package:
apt-get update && apt-get install firmware-atheros
4. Connect device to your system, or reboot