If you have forgotten your password on the AP35XX, use the following process to reset the password to its default value:
Step 1.  Serial up to the AP3500/AP4700 with 19200-8-N-1    
Step 2.  Power cycle the AP3500/AP4700    
Step 3.  Press the “Escape” key when the AP3500/AP4700 states “Press escape key to run boot firmware”.     
Step 4.  From the “boot>” prompt enter “passwd default”.     
Step 5.  Reset the system by entering “reset system”.
The default username is admin.  The default password is admin123.