you can short out the cables in the rooms one at a time and then use an OHM meter to look for the cable that is shorted.i used this to determine which cable went to which room.
Put a small DC voltage (like with a 9-volt battery) on a cable and then go to the other end and look for which one has 9 volts on it.
Since you are looking for the input I guess use process of elimination.
-------- Original message --------
From: Keith Wright via WLUG <wlug@lists.wlug.org>
Date: 9/7/23 14:21 (GMT-05:00)
To: Worcester Linux Users' Group General Discussion <wlug@lists.wlug.org>
Cc: wlug@lists.wlug.org, kstratton@fastmail.us, Keith Wright <kwright@keithdiane.us>
Subject: [WLUG] Re: I need advice on a new ISP
Kevin Stratton via WLUG <wlug@lists.wlug.org> writes: