Canon EOS 7D Mark II (G) Instruction Manual page 260

D Using an External Speedlite
Canon Speedlites Other Than the EX-series
With an EZ/E/EG/ML/TL-series Speedlite set to A-TTL or TTL
autoflash mode, the flash can be fired at full output only.
Set the camera's shooting mode to <a> (manual exposure) or
<f> (aperture-priority AE) and adjust the aperture setting before
shooting.
When using a Speedlite that has manual flash mode, shoot in the
manual flash mode.
Non-Canon Flash Units
Sync Speed
The camera can synchronize with non-Canon compact flash units at
1/250 sec. and slower speeds. With large studio flash units, be sure to
test the flash synchronization before shooting with the sync speed set
within approx. 1/60 sec. to 1/30 sec. The flash duration of such units is
longer than that of compact flash units and varies depending on the
model.
PC Terminal
Cautions for Live View Shooting
If you use a non-Canon flash unit with Live View shooting, set [z6:
Silent LV shoot.] to [Disable] (p.297). The flash will not fire if it is set to
[Mode 1] or [Mode 2].
260
The camera's PC terminal can be
used with flash units having a sync
cord. The PC terminal is threaded to
prevent inadvertent disconnection.
The camera's PC terminal has no
polarity. You can connect any sync
cord regardless of its polarity.