28th May 2005 at 04:08
#28178
Guest
There are some small plastic boxes that are used on elevator phones, that do exactely waht you need.
They do not need power, they take voltage from the line.
I rememeber one brand “hotdialer”, do not know if it still around.
That was a very basic unit, with dip switches under the cover for programing.
Very nice ,since did not loose the programing (very hard to loose suitcase plugs)
Best luck to you.