Making an MMJ cable is a piece of cake. Just take the retention clip
off of the RJ11 at the end of a phone cord. Crimp an RJ45 on the other
Rememeber the OP (and I) are in the UK. The standard telephone connector
over here is not an RJ11 or snythig like that.
end with the proper wires heading to the proper pins,
and use a Cisco
RJ45->DE9 adapter.
Having had to try to get wires into the right holes on an RJ45 connector,
I would _much_ rather solder up a D connector.
-tony