HP 8753E Programming And Command Reference Manual page 165

Begins the transmission calibration
subsequence of a 2-port calibration.
Begins the transmission calibration
subsequence for one path, two port
calibration.
Same as S21.
Measures TRL Line/match for Port 1
during a TRL/LRM 2-port calibration.
Measures TRL Line/match for Port 2
during a TRL/LRM 2-port calibration.
Measures TRL Sll reflect during a
Measures TRL S22 reflect during a
Measures TRL thru during a TRL/LRM
Same as CSWI.
Causes a self test and returns a zero if the
test is passed.
HP-IB Programming and Command Reference Guide