How to check wifi networking standard of current connection

Solution 1:

On Windows (tested on Win7, should be compatible with Vista back to Windows XP):

C:\Users\kuba>netsh wlan show interfaces

There is 1 interface on the system:

    Name                   : Wireless Network Connection 2
    Description            : DW1520 Wireless-N WLAN Half-Mini Card
    State                  : connected
    Network type           : Infrastructure
    Radio type             : 802.11g         <-- the currently negotiated value
    Authentication         : WPA-Personal
    Cipher                 : CCMP
    Connection mode        : Auto Connect
    Channel                : 11
    Receive rate (Mbps)    : 54
    Transmit rate (Mbps)   : 54
    Signal                 : 82%
    Profile                : xxxx

    Hosted network status  : Not started

On many Linux flavors (including Debian) use iwconfig. Although it doesn't display a string such as "802.11n", it does display Bit Rate:54 Mb/s among other settings.