HP 3336A Operating Manual page 61

Appendix A
To make the -hp- 3336 return specific information about its operating state:
First:
BUS MANAGEMENT LINES
ATN IFC SRQ REN EOI one aa is on Data lines
T F X T Xx ? U_ $
L_ 3336 listen address
controller talk address
universal unlisten (077g)
Second:
BUS MANAGEMENT LINES
ATN
IFC SRQ REN
EOI
sequence on Data lines
F F Xx T Xx interrogate Program Instruction
Third:
BUS MANAGEMENT LINES
T F Xx T x ? OD 5
ae address of device
receiving data
-hp- 3336 talk address
universal unlisten (0778)
Fourth:
BUS MANAGEMENT LINES
ATN IFC SRQ REN
EOI
sequence on Data lines
Figure 3-A-7. Data (receive).