W. P. McGown wrote:
> Mike,
>
> Many thanks for the speedy reply but I donąt see how that is going to help
> me trigger the shutter of my 990 from a relay controlled by a computer.
> This computer is an Arduino board with digital logic level outputs. I will
> use one of these to control a small relay.
>
> Maybe Iąm dense but could you give me a little more info.

Try these guys - https://www.harbortronics.com/

They have products that communicate with the 990 via the serial port and
accept relay closures as trigger events.