Question: does rj12 fit into rj45?
Answer: The plugs and jacks are wider than their RJ12 counterparts - 7/16"vs 3/8". An RJ45 male plug won't fit into an RJ12 female jack. But an RJ12 male plug will fit into an RJ45 female jack. A lot of RJ12 female jacks are really RJ45 jacks in disguise!