Canon 600EXII-RT Instruction Manual page 97

If there is a fluorescent light or computer monitor near a slave unit, the
presence of the light source may cause the slave unit to malfunction and
fire inadvertently.
During optical transmission wireless shooting, even if the master and
slave units (firing group) are not all fully charged, <G> will not be
displayed on the master unit's LCD panel as it is with radio transmission
wireless shooting (with master flash firing OFF). Also, there is no function
for illuminating or turning off the master unit's LCD panel according to the
charge status of the master unit and slave units.
When C.Fn-20-1 is set on the master unit (p.116), the beep will sound
when the master unit is fully charged. (This beep does not indicate that
charging of all flash units is completed as it does with radio transmission
wireless shooting.)
a: Fully Automatic Wireless Flash Photography
Position the camera and the flash.
4
Position them within the range shown
on page 90.
Set the flash mode to <a>.
5
Press the <E> button on the
master unit.
Turn <9> to select <Q>, then
press <8>.
The slave unit is set automatically to
<a> during shooting, controlled
by the master unit.
Check that the firing group control is
set to <t>.
Check that the flash is ready.
6
When the slave flash is ready, the AF-
assist beam emitter blinks with
approx. 1-second intervals.
Check that the master unit's flash-
ready lamp is lit.
97