When I had to setup the run cable for our phone system and Internet. We had many types of wires in the ceiling: FTP, STP, and UTP cables. FTP is foiled twisted pair. The foil is used to block out EMI (electro magnetic interference). In order for the shielding to be most effective, the shielding should be grounded. We had darker gray cat 5 FTP wires, which most of them were cut in the ceiling but the beige jacks were still in place. We used a tone generator and amplifier probe to track the dead wires in the ceiling and through the walls. The existing wires that were run to our 48 port patch panels used cat 5e UTP, which is unshielded twisted pair that doesn’t offer the same kind of protection against EMI, but is more cost effective. Wires are twisted for inductive coupling that will significantly reduce EMI which can result in poor signal quality.
Entry by: T-Bone