User`s guide

Remarks
When you first receive your instrument, it is secured. The security code is
set to "AT34410", "AT34411", or "ATL4411" when the instrument is
shipped from the factory.
Once you enter a security code, that code must be used for both front-
panel and remote-interface calibration. For example, if you secure the
instrument from the front panel, you must use that same code to unsecure
it from the remote interface.
Unsecuring the instrument using this command enables the instrument to
be calibrated.
To calibrate the 34410A, 34411A, or L4411A use the CALibration:VALue
and CALibration? commands.
The calibration security setting 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).