• Check your installed PCIE Hardware:

lspci
dmesg | less 

• An example of this command could be:

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:16.3 Serial controller: Intel Corporation 6 Series/C200 Series Chipset Family KT Controller (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4)
00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b4)
00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b4)
00:1c.4 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5 (rev b4)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation QM67 Express Chipset Family LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 04)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 04)
03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)
0d:00.0 System peripheral: Ricoh Co Ltd MMC/SD Host Controller (rev 04)

• Look for name or brand or model of your wireless card in the previous list:

03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)

• Then look for a package with a similar name but with firmware in the package name somewhere: for example:

apt-cache search intel firmware

• Any one of this may be:

firmware-intelwimax - Binary firmware for Intel WiMAX Connection firmware-ipw2x00 - Binary firmware for Intel Pro Wireless 2100, 2200 and 2915 firmware-iwlwifi - Binary firmware for Intel PRO/Wireless 3945 and 802.11n cards

• You can try to see more description details of these packages to get the right one, eg:

apt-cache show firmware-iwlwifi

• Then if this is the one you need you have to install it:

sudo apt-get install firmware-iwlwifi

* If you are not sure, just install all the packages starting with firmware that have intel brand somewhere in the description.
* In case the kernel module was already loaded (usually this is the case), you have to restart it to force the card to load the firmware files:

sudo rmmod iwlwifi
sudo modprobe iwlwifi

• Check the output of the kernel with the command:

dmesg

• You will see something similar to this near the end of the output of the last command:

[24912.746055] iwlwifi 0000:03:00.0: firmware: agent loaded iwlwifi-6000g2a-5.ucode into memory
[24912.746061] iwlwifi 0000:03:00.0: loaded firmware version 17.168.5.3 build 42301

• If you don't get any of this, please reboot the computer.

• If you have yet to install a graphical enviroment for your debian you could configure your wireless device by console,for that purpose the next guide may solve your problem, if it doesn't you might want to search for similar topics online, you can always check your network information by entering “cat /etc/network/interfaces” ”. First you must enter the file:
  

                                     “etc/network/interfaces”
                                     

Then the file entry should be as the following:

                                         
                                     “ allow-hotplug wlan0
                                       iface wlan0 inet dhcp
                                       wpa-ssid homezone"
                                       
                                       

Next to be done is to write the following lines,with the needed changes, in “etc/network/interfaces”:

                                     “allow-hotplug wlan0
                                      iface wlan0 inet dhcp
                                      wireless-essid Home
                                      wireless-key1 1111-2222-33ab-cdef
                                      wireless-key2 44444444
                                      wireless-key3 s:password
                                      wireless-defaultkey 2
                                      wireless-keymode open"            
                                                      

verify with “ifdown wlan0” and “ifup wlan0”

The best connection manager!

• Install the following packages:

sudo apt-get install connman connman-ui connman-gtk

• Remove all other connection managers
• Restart connman:

sudo systemctl restart connman.service

• Run connman-ui-gtk from a console and let it detach

nohup connman-ui-gtk &

• You will get an icon in your panel. Right-click it and be sure to activate WIFI.
• The Left-click it and select your desired network.
• If the network requires a password connman-ui-gtk will ask for it now.
• To start the connman-ui-gtk automatically everytime you login, in your panel, go to Applications→Settings→Session and Startup→Application Autostart
• Press +ADD
• Fill in the fields and be sure to put in “Command”: “connman-ui-gtk”
• You are done!

• You need to install a certificate from Centro de Informática. For that you have to run the Linux Installer script (made only for Network Manager). This script will install the certificate in your home in ~/.cat_installer/ca.pem
• Download and run the installation script from centro de informática: https://ci.ucr.ac.cr/auri/
• Make a text file /var/lib/connman/eduroam.config with the following content:

[service_eduroam]
Type=wifi
Name=eduroam
EAP=ttls
CACertFile=/home/username/.cat_installer/ca.pem
Phase2=PAP
Identity=*your ucr email address*
AnonymousIdentity=anonymous@ucr.ac.cr
Passphrase=*your_password*

• The certificate that centro de informática distributes is old and obsolete. You need to add the following to the file /etc/wpa_supplicant/wpa_supplicant.conf (create the file if it doesn't exist):

OPENSSL_ENABLE_MD5_VERIFY=1

• Kill any wpa_supplicant that is running and restart connman. (Restart your computer if you have troubles with this)
• Connect to eduroam. It should work!

• Install wicd:

sudo apt-get install wicd-gtk wicd
sudo /etc/init.d/wicd restart

• Run wicd-gtk

wicd-gtk

• Close your session while the console running wicd-gtk is still open. This normally will bring wicd-gtk automatically up in the next logging in.
• Configure wicd wireless interface in the preference button. Put : wlan0
• Press “refresh” and select and configure your wireless network as needed.

• Copy the next text into a file called eap-ttls in directory /etc/wicd/encryption/templates :

name = TTLS for Wireless
author = Alexander Clouter
version = 1
require  identity *Identity password *Password 
protected password *Password
optional ca_cert *Path_to_CA_Cert cert_subject *Certificate_Subject anon_identity *Anonymous_Username
-----
ctrl_interface=/var/run/wpa_supplicant
network={
     ssid="$_ESSID"
     scan_ssid=$_SCAN

     key_mgmt=WPA-EAP
     eap=TTLS

     ca_cert="$_CA_CERT"
     subject_match="$_CERT_SUBJECT"

     phase2="auth=PAP"

     anonymous_identity="$_ANON_IDENTITY"
     identity="$_IDENTITY"
     password="$_PASSWORD"
}

• In that same directory edit the file called “active” and add “eap-ttls” at the end.
• Restart wicd:

/etc/init.d/wicd restart

• That's it. Now when configuring AURI3-UCR select “TTLS for Wireless” and using your username and password from the “portal de la UCR”

• Not recommended: it will install all gnome-$%#! …
• Install a network manager:

sudo apt-get install network-manager network-manager-gnome

• Restart the network-manager:

sudo /etc/init.d/network-manager restart

• Inside of your desktop environment open a console and run:

nm-applet

• You now will see a small applet icon in your application bar. Just select your desired wireless network.
• Please don't close the console that is running nm-applet. You should now log out and log in and the applet should run automatically. If not, add the nm-applet aplication in your autostart applications in the session and start section of the settings of xfce4.