Canon MX420 - Manual (Page 8)

Step Five
Select the access point name, then press the OK button.
NOTE: If you are living in an apartment, nearby access
points in use may be detected.
Step Six
When one of the following screens is displayed, enter the network
key using the Numeric buttons (E), then press the OK button.
If the following screen is not displayed, go to step 8
Press the button to switch character entry modes.
Network key entry is case-sensitive.
Be sure to enter upper and lower case letters of the alphabet
correctly
Adding Your Multifunction to Your Network
8