Step 1 Open a web browser and type the IPaddress of the DSL-2640B router into the address bar (default ishttp://192.168.1.1). Press Enter.
Step 2 The default username is admin (all lowercase) and the default password is admin (all lower case). Click onOK.
Step 3 Click on the Setup tabat the top and then click on Wireless on theleft-hand side.
Step 4 Under Security Mode click on the dropdown menu.
Step 5 Choose the security mode desired. Theavailable modes are WEP,WPA-Personal,WPA-Enterprise homeusers will want to use WPA-Personal orWEP (Please Note that WPA is more secure thenWEP).
Step 6 Choose WPA only forhigher compatibility this mode uses TKIP cipherand some gaming and legacy devices work only with this mode.
Step 7 Enter the desired Pre Shared Key in thePre-Shared Key Box. The Pre Shared Key has aminimum of 8 characters and a maximum of 63 characters. You can useany letter or number on the keyboard. Please note that the PreShared Key is case sensitive, "A" is not equal to "a".
Step 8 Apply settings andreboot the router for the changes to take affect.
A copy of this FAQ (with screenshots) can be downloaded here.