IT / Telecom Infrastructure / Structural Cabling 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 various kinds of cable, most commonly category 5e (CAT-5e), category 6 (CAT-6), and fibre optic cabling and modular connectors. These standards define how to lay the cabling in various topologies in order to meet the needs of the customer, typically using a central patch panel (which is normally 19 inch rack-mounted), from where each modular connection can be used as needed. Each outlet is then patched into a network switch (normally also rack-mounted) for network use or into an IP or PBX (private branch exchange) telephone system patch panel. Although each site is different, and care must be taken to account for special needs if they exist, for the most part these standards conform to ANSI TIA/EIA-568-B documents. There are some additional requirements, and, in some cases, minor exceptions to the published TIA/EIA standards.