This page is to get you a good start for using Bluetooth on Debian.
We asume that you have a mobile phone and want to exchange data between that device and your Debian system.
Install as root the Bluetooth main package.
aptitude install bluez-utils
You will now have an idea that Bluetooth high tech is.
Also you have seen the term pairing. For the pairing you need a passkey-agent
aptitude install gnome-passkey-agent
On your mobile you can now try to pair. Steps involve going to a "setup","connect" or "Bluetooth" menu and then select to search for BT devices. Your Bluetooth phone will/should see a BT device that is named bahrain-0, where bahrain the hostname your Debian GNU/Linux computer is. Select the computer on your phone. Next will the phone ask for a PIN, you can make one up. ( chose four digits, say 2309 )
On your computer will gnome-passkey-agent pop-up an information balloon with text like Pairing request from BtPhone (19:25:12:16:50:53) where BtPhone is the name of your Bluetooth phone and 19:25:12:16:50:53 is it's BT MAC address.
Click in the information balloon.
Another window will pop-up. It asks for the PIN, enter the one you just made up. (e.g. 2309 ) and press enter.
Your phone sees that the PIN matches and shows it on it's display.
Both devices are now paired.
further help requested