IOtech Digital488 - Selected Device Clear (SDC); Serial Poll Disable (SPD); Serial Poll Enable (SPE); Group Execute Trigger (GET)

Section 4 IEEE 488 Primer
4.9
4.7.8 Selected Device Clear (SDC)
This causes a single device to be initialized to a pre-defined or power up
state. ($04)
4.7.9 Serial Poll Disable (SPD)
The
SPD
command disables all devices from sending their Serial Poll
status byte. ($19)
4.7.10 Serial Poll Enable (SPE
)
A device which is Addressed to Talk will output its Serial Poll status
byte after
SPE
is sent and
ATN
is unasserted. ($18)
4.7.11 Group Execute Trigger (GET)
This command usually signals a group of devices to begin executing a
triggered action. This allows actions of different devices to begin
simultaneously. ($08)
4.7.12 Take Control (TCT)
This command passes bus control responsibilities from the current
Controller
to another device which has the ability to control. ($09)
4.7.13 Secondary Command Group (SCG)
These are any one of the 32 possible commands (0 to 31) in this group.
They must immediately follow a talk or listen address. ($60 to $7F)