Measurement Computing Isolator488 - Manual (Page 30)

Section 3 IEEE 488 Primer
3-9
3.7.8 Selected Device Clear (SDC)
This causes a single device to be initialized to a pre-defined or
power up state. ($04)
3.7.9 Serial Poll Disable (SPD)
The SPD command disables all devices from sending their Serial
Poll status byte. ($19)
3.7.10 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)
3.7.11 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)
3.7.12 Take Control (TCT)
This command passes bus control responsibilities from the current
Controller to another device which has the ability to control. ($09)
3.7.13 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)