Sorry to have to ask such a noob question, but...

I ported our home number to 2talk years ago and have been happily using a softphone.
Am now in the process of setting up a physical handset (shock, horror!) so that kids can answer phone etc.

So I have a Netcome Wireless NF5 and have just purchased a Panasonic cordless handset which came with a RJ11 on one end and a connector to standard phone port (BT?) on the other.

Unless I'm mistaken, I just need to get an RJ12<->RJ12 to connect phone base station to VOIP port on NF5? Or RJ11<->RJ11? Or neither?