CAT5/CAT6 Cables

The categories represent progressively better cable performance. CAT5 supports 10/100 Mbps Ethernet at 100 MHz and is nearing the end of its useful life. CAT5e (enhanced) is the most widely deployed cable and supports Gigabit Ethernet (1 Gbps) at 100 MHz, with reduced crosstalk between pairs. CAT6 supports 10 Gbps at 250 MHz for short distances (up to 55 meters). CAT6a supports 10 Gbps at 500 MHz for full 100-meter runs. CAT7 supports 10 Gbps at 600 MHz with even better shielding, but uses non-standard connectors. For new commercial installations, CAT6 is the typical minimum, with CAT6a for 10 GbE infrastructure.

CAT6 is the typical minimum for new commercial AV installations, supporting Gigabit Ethernet, PoE, HDBaseT, and most AV-over-IP applications reliably. CAT6a is the right choice for 10 Gigabit Ethernet infrastructure and for future-proofing high-bandwidth AV-over-IP networks. CAT5e is still acceptable for budget-constrained installations that need only Gigabit Ethernet, but the small additional cost of CAT6 is usually worth it for future-proofing. For specialized environments with high electromagnetic interference, consider shielded (STP) cable in the appropriate category.

The standard maximum is 100 meters (328 feet) for any category of twisted-pair Ethernet, including patch cables on each end. Beyond 100 meters, signal integrity drops and Ethernet errors increase to unacceptable levels. For longer runs, use fiber optic cable (single-mode for very long distances, multimode for moderate distances within a building), an Ethernet repeater or switch in the middle of the run, or extension technology specific to the signal type (such as fiber-based HDBaseT extenders).

Unshielded twisted-pair (UTP) is the standard for most installations: the twisted pairs themselves cancel out enough interference for normal use, and the cable is cheaper and easier to terminate. Shielded twisted-pair (STP) is the right choice for environments with high electromagnetic interference (near power cables, motors, fluorescent lights, dimmers), for full-length 10 Gigabit Ethernet runs (where the higher frequencies are more susceptible to interference), or in industrial and medical environments where reliability and noise rejection matter more than cost.

Plenum cable (CMP-rated for communications) has a jacket made of materials that produce minimal toxic smoke when burned, making it safe for installation in return-air plenum spaces in commercial buildings. Plenum spaces are the ceiling cavities above suspended ceilings that carry forced HVAC return air; smoke that enters these spaces during a fire spreads through the building, so plenum cable is required by building and fire codes for any cable installed in these areas. Riser cable (CMR-rated) is required for vertical runs between floors, with less stringent fire requirements than plenum.

Networked AV devices (AV-over-IP encoders and decoders, IP cameras, networked audio devices using Dante or AES67, IP-controlled displays and projectors), HDBaseT extenders (which carry HDMI signals over 100 meters on a single CAT6 cable), PoE-powered devices (security cameras, wireless access points, IP phones, some AV displays, network speakers), control system processors and touch panels, and general networking infrastructure (switches, routers, servers). In most modern AV installations, CAT cable far outnumbers HDMI runs, because everything talks IP first and HDMI second.