Wired triggering of cameras.

Pamco-Imaging turntables with optional wired triggering use a 3.5mm (TRS) jack to connect to cameras which have wired triggering.

T = shutter
R = 1/2 detent (meter)
S = Ground

The T and R each have a separate software controlled relay inside the turntable.
The software triggers the relays to simulate a hand held wired remote.
The 1/2 detent closes first then a split second after the shutter contact closes for about 1 second.
This sequence replicates a user pressing a hand held wired remote trigger.