Many questions for RUT were answered in a lecture at Jahreshauptversammlung in Rheine. These are now written in a pdf sheet (German only).

Stefan Seibt has on the pages for Freundeskreis TT compiled a nice summary: TT-RUT

For each station / operating point should be a phone. Whether they're impulse or tone regime is unimportant, telephone installations are then set.

The usual connector is a 6-pole Western plug (RJ11), where the middle 2 contacts Adern La and Lb, are taken from the phone. If your phone has a TAE socket, then there is usually achieved via an adapter connected to the RUT system.