There a two possibilities, one where TILLvisION takes control (as master) and another where TILLvisION gets controlled (as slave).
TILLvisION (TILL Imaging System) as Master
TILLvisION says when to acquire a current/voltage trace. Just connect a trigger line from port 1 of the ISC to the external trigger input of your electrophysiology software. See the sample protocol below: the Protocol Editor will send a TTL pulse at the beginning of each loop.
TILLvisION as Slave
Electrophysiology Software says when to take a picture or ratio. Just connect a trigger line from the interface to port C of the ISC. See the sample protocol below: the Protocol Editor will wait for a TTL pulse before executing one loop of the repeat.
TILLvisION is the integrating part of the TILL Imaging System. You may also want to take a look at the features page.