"Graham J" wrote in message
Use the cable provided with the router to connect the RJ11 socket on the
router (marked DSL or similar) to the RJ45 socket which extends the
unfiltered phone line. I know the RJ11 plug looks too small to fit the
RJ45 socket, but it does fit and is the way that Openreach do it.
I thought that the edges of an RJ11 plug fouled the extra pins at either end
of an RJ45 socket and could damage them. I was always taught that you should
never insert an RJ11 into an RJ45, along with various imprecations about the
parentage of the person who designed the smaller plug so it could
"sort-of-fit" into the larger socket.