Agilent Technologies E4991A Service Manual page 355

Messages
User cal mode only
does not provide any problem. For example, when the program message
"DISP:TRAC1:X:AUTO" has been sent instead of the correct program message
"DISP:TRAC1:Y:AUTO", it is received by the E4991A as an undefined command.
Refer to the command reference and check the correct commands.
15 User cal mode only
Setting has been attempted by using commands to define each standard of the calibration
kit before selecting a user defined calibration kit.
First select the calibration kit that will be used as the user defined calibration kit. Then
define each standard value for this calibration kit.
Appendix E 355