My master socket has one RJ11 and one BT Connector.
On the inside there is a Krone strip for a single pair.
I've made a cable that connects from the openreach modem and connects to the single pair connector.
(the cable is solid and not stranded)
Only reason to do this was to move the openreach modem nearer the master and plug it in to a mains socket on a different circuit to the main house.
My pfSense router has detected the connection and reconnected without issue.