That's a lot clearer thanks.
Just to explain that an RJ11 DSL splitter does two things
1. Feeds the phone line wires from one socket to two.
2. Removes (filters out) the DSL signal from the socket marked analogue/phone.
Particularly for 2. it makes sense to use the RJ11 DSL splitter you already have.
I think the best solution is what you tried oriiginally! Connect your RJ11 splitter directly to the patch panel RJ45 socket where your broadband phone line is. Then take two standard phone or modem cables (RJ11 plugs on both ends, with the wires passed straight through). Connect one between the splitter's DSL socket and the DSL port on your firewall/router, and connect the other between the splitter's analogue port and your fax machine (or back into an input port on your patch panel, if you want to patch it somewhere else in the building.).
Things would then look something like
Code:
__DSL modem/router
phone__|patch|RJ45 :RJ11|DSL filter|RJ11 :
line |panel|socket:plug|/ splitter|sockets:__phone/fax/modem/patch panel
That should work, assuming your comms installer used the middle pairs for the phone line, so you can just plug an RJ11 connector into the RJ45 socket. I think this is all you were missing originally, so apologies if I over-complicated things. When I wrote my original reply, I'd forgotten that RJ11 plugs are physically compatible with RJ45 sockets (It's a few years since I've been near a patch panel!). If you have analogue phones, look at where they connect to the floor or wall socket. You will probably find an RJ11 plug on the phone cable going into an RJ45 socket.
If your RJ11 splitter (the body, not the connector) is too wide to fit into your patch panel, just get a short phone extension cable (RJ11 plug on one end and RJ11 socket on the other) and insert that between the panel panel and the splitter.
Let us know how you get on.