Start stop on two HPX170

[Mike Hanlon]

Need some engineering advice.

I would like to have my Varizoom controller connect to two HPX170s at the same time, but I only need the start/stop function. I have discovered the pinout for the SS connector (2.8mm TRS) to be:

T - start/stop, pulled high (to what I don't know)
R - variable voltage controls zoom in and out
S - reference/ground

Start/stop toggling is accomplished by connecting T and S (grounding T). My plan would be to use a Y adapter on camera 1, plug the Varizoom in the the adapter, then make a cable to go from the other side of the Y to camera 2, but the cable would only have T and S wired up.

My concern is connecting both cameras' T and S to each other, which is what I would have. If I was sure to have bother cameras powered before plugging/unplugging the cables, would that help?

I also considered a somewhat more complicated arrangement where I construct the Y adapter myself and add a couple of diodes to the T so that current won't flow between cameras, but is that more than is needed?

Of course the simplest solution is to just connect a momentary switch to T and S of camera 2.

Thanks.