What is the easiest way to run telephone cable between floors without fishing them through the walls?
I'd stay away from tape (it may only stick for a few months) and ceilings as well. Just do what the phone company has always done. Staple or nail the wires down to the baseboard or the underside of the baseboard's cap (if any) or tuck the wire down beside wall-to-wall carpet. You continue this right up the stairs to the other room and its all easy to literally rip out when you no longer need it.