It is posible to use a normal timer. I have a normal timer with it's own foot switch connected to mine.
I'll have a look at my set-up tomorrow to see exactly what I did when I originaly set the enlarger up.
By the way, I left the chain covers off my enlarger. After I finally figured out how to put the chains on, that is. This was pre internet days.
This allows me to lubricate the chains every year with motorcycle chain lube, which as most motorcyclists know, sticks like excrement to a blanket.
If I remember correctly, I had an electrician mate figure how to wire, (safely) power into the transtab.
Mick.