|Actually it is Cat 5 unshielded twisted pair cable (UTP) that you need . Shielded twisted pair (STP) is used in high EMI environments. For the shield to be of any use it has to be grounded and that can cause ground loop problems if not done correctly and can even be a fire risk.|
In a home or office UTP cable is more than adequate. Protection from interfereance is achieved by the twissted pairs.