Canon SPEEDLITE EL-1 Advanced User's Manual page 20

Receiver unit
(1)
(2)
(3)
(1) < > Receiver
(2) < > Transmission channel
(3) < > Test flash*
< > Remote release*
< > Modeling flash*
(4) < > Receiver setting
(5) <
* 1: < > Radio transmission wireless only
* 2: < > Optical transmission wireless only
1
1
1
> Individual receiver*
20
(4)
(5)
2