HP 8753E Programming And Command Reference Manual page 129

These commands enter labels (max. length = 10 char) for the standard
classes during a cal kit modification:
1-122 HP-IB Progmmnu 'ng and Command Reference Guide
Sends a keycode, equivalent to actually
pressing the key. It does not matter if
the front-panel is in remote mode. See
Figure l-6 for the key codes.
Calibration kit done. This is the last step
in modifying a cal kit.
Outputs last key code or knob count. If
the reply is positive, it is a key code. If it
is negative, then set bit 15 equal to bit 14,
and the resulting two byte integer is the
RPG knob count. It can be either positive
or negative. There are about 120 counts
per turn.
Forward match.
Forward transmission.
Response, response and isolation.
Response.
Reverse match.
Reverse transmission.
TRL line or match.
TRL thru.
TRL reflect.
TRL, Line, Forward, Match. Compatible
with
the HP 8753D revisions 5.00 through