Got a VOIP modem with an RJ11 socket?If you are lucky enough to have either a wireless or cable connection to the internet, you can almost undoubtedly save money on line-rental by getting rid of your landline and move over to VOIP instead.
However, in the UK we have BT 431A plugs and most modems/adapters have RJ11 sockets on them. Therefore an adapter is needed but which one?
STOP Press - I found this useful post here - It shows us that the middle two pins (3 and 4) are line 1 and the next two pins (2 and 5) are line 2.
Speaking from my experience with my Draytek 2820Vn router you need to choose a crossover type. The information about how to connect a BT designed device to these things is difficult to find, mainly because you don't know what to type into the Google search box!
Useful information I found is available to browse HERE, with the most important paragraph being the last one. It states that pins 2 and 3 of the RJ11 plug need to be crossed-over to connect to pins 3 and 2 of the BT plug/socket. Similarly, pins 4 and 5 need to be crossed-over and connected to pins 5 and 4 of the BT plug/socket.
To quote the web-site: "NORMALLY the center two pins on the RJ11 are connected to the outer two (2 and 5) at the BT end. No matter what coloured wire is used the two wires always go to pins 2 and 5 at the BT end however it isn't safe to assume they ALWAYS go to the center two at the RJ11 end."
Just to test, I ordered this from eBay - search for a "BT Socket to RJ11 Plug 4 Pin UK Telecom Telephone Phone Cable Adaptor Converter" and you shouldn't go far wrong.
For some nice VOIP information, have a look at this article and this one too for Draytek related information.