Structured cabling design and installation is governed by a set of standards that specify wiring data centers, offices, and apartment buildings for data or voice communications, using category 5 (CAT 5E) or category 6 cable (CAT 6E) and modular sockets. These standards define how to lay the cabling in a star formation, such that all outlets terminate at a central patch panel (which is normally 19 inch rack-mounted), from where it can be determined exactly how these connections will be used. Each outlet can be 'patched' into a data network switch (normally also rack mounted alongside), or patched into a 'telecoms patch panel' which forms a bridge into a private branch exchange (PBX) telephone system, thus making the connection a voice port. The latest standard from the TIA for enhanced performance standards for twisted pair cable systems was defined in February 2008 in ANSI/TIA/EIA-568-B.2-10. Category 6a (or Augmented Category 6) is defined at frequencies up to 500 MHz—twice that of Cat. 6. Category 6a performs at improved specifications, particularly in the area of alien crosstalk as compared to Cat 6 UTP which exhibited high alien noise in high frequencies. Category 7 cable (Cat 7), (ISO/IEC 11801:2002 category 7/class F), is a cable standard for Ethernet and other interconnect technologies that can be made to be backward compatible with traditional Cat 5 and Cat 6 Ethernet cable. Cat 7 features even more strict specifications for crosstalk and system noise than Cat 6.
