I always use an RJ45 jack at the wall end as well. RJ11 connectors are compatible with RJ45 jacks. You just use the two center contacts (pins 4 and 5 or the blue pair of wires) for line 1 on your telepone. If you are using a 2-line phone, you would use pins 3 and 6 for the second line. This would be the orange pair if you are using the T568A standard or the green pair for 568B. You can find a more detailed explanation here and here . Hope this helps with your question.
Mark
Mark