UTP (Unshielded twisted-pair) cable relies solely on the cancellation effect produced by the twisted wire pairs to limit signal degradation caused by electromagnetic interference (EMI) and radio frequency interference (RFI). FTP (Foil screened twisted-pair) is also called ScTP (Screened twisted-pair). It is improved from UTP, combining the technique of shielding, but only wrapped in an overall metallic braid or foil. Many cable installers and manufacturers may use the term STP to describe FTP cabling. Exactly, STP (Shielded twisted-pair) is different from FTP. STP cable combines the techniques of shielding, cancellation, and wire twisting. Each pair of wires is wrapped in a metallic foil. The four pairs of wires then are wrapped in an overall metallic braid or foil. As specified for use in Ethernet network installations, STP reduces electrical noise both within the cable (pair-to-pair coupling, or crosstalk) and from outside the cable (EMI and RFI). Although STP prevents interference better than UTP and FTP, it is more expensive and difficult to install. The metallic shielding must be grounded at both ends. If it is improperly grounded, the shield acts like an antenna and picks up unwanted signals. Because of its cost and difficulty with termination, STP is rarely used in Ethernet networks. STP is primarily used in Europe