HP 8753E Programming And Command Reference Manual page 161

The following 7 commands (OPC-compatible) select a standard from
a class during a calibration sequence. If a class is requested, as in
there is only one standard in the class, it will measure that standard
automatically. If there are several standards in the class, then one of
the following commands must be used to select one of these standards,
causing it to be measured.
Selects the desired segment of the
frequency list for a list frequency sweep.
See also ASEG. Range: 1 to 30.
Outputs the status byte. Same as
OUTPSTAT.
Standard listed under softkey 1.
Standard listed under softkey 2.
Standard listed under softkey 3.
Standard listed under softkey 4.
Standard listed under softkey 5.
Standard listed under softkey 6.
Standard listed under softkey 7.
Enters the start stimulus value. If a list
frequency segment is being edited, sets
the start of the segment. Range: stimulus
range.
Standard done, terminating a define
standard sequence, while modifying a cal
kit.