HP 16554A Programmer's Manual page 298

DATA and SETup Commands
Acquisition Data Description
The depth of the data array is equal to the pod with the greatest number of
rows of valid data. If a pod has fewer rows of valid data than the data array,
unused rows will contain invalid data that should be ignored.
The clock pod contains data mapped according to the clock designator and
the board (see below). Unused clock lines should be ignored.
Where x = not used, mstr = master card, exp# = expander card number.
Byte Position
2 bytes - Not used (clock pod 2).
591
1 byte - MSB of clock pod 1.
593
1 byte - LSB of clock pod 1.
594
1 byte - MSB of data pod 4, board x.
595
1 byte - LSB of data pod 4, board x.
596
1 byte - MSB of data pod 3, board x.
597
1 byte - LSB of data pod 3, board x.
598
1 byte - MSB of data pod 2, board x.
599
1 byte - LSB of data pod 2, board x.
600
1 byte - MSB of data pod 1, board x.
601
1 byte - LSB of data pod 1, board x.
602
.
.
where n = 591 + (bytes per row × maximum number of valid rows) - 1
Byte n
17–12
Clock Pod 1 < xxxx MLKJ MLKJ MLKJ >
exp2 exp1 mstr