User`s guide

Remarks
The security codes for the 34410A/11A/L4411A are set to "AT34410",
"AT34411", and "ATL4411" respectively when the instruments are
shipped from the factory.
If you forget your security code, you can override the security feature. See
the Agilent 34410A/11A/L4411A Service Guide for more information.
The security code is stored in non-volatile memory, and does not
change when power has been off, after a Factory Reset (*RST
command), or after an Instrument Preset (SYSTem:PRESet
command).