How Cabling Has Changed: From Cat5 to the Modern Structured Cabling Era

If you have been in IT for more than a decade, you have watched the physical foundation of networking transform in ways that would have seemed implausible in the early 2000s. Cabling has undergone a quiet revolution driven by speed demands, power delivery, and wireless-first architecture.

From Cat5 to Cat6A

Cat5 cable maxed out at 100 Mbps over 100 meters. Cat5e extended this to Gigabit Ethernet and dominated office installations for nearly two decades. Cat6 brought 10 Gbps at up to 55 meters. Cat6A extended 10 Gbps to the full 100-meter channel length and is now the TIA-568 recommended minimum for new installations. Specifying anything below Cat6A for a new build today means designing an infrastructure that will need replacement within its useful service life.

PoE Changed Everything

Power over Ethernet has changed the economics of device deployment more than any other cabling development. From 802.3af at 15.4W for IP phones to 802.3bt Type 4 at 100W for thin clients, PoE now powers wireless access points, IP cameras, door readers, and VoIP phones over the data cable. Cat6A is required for high PoE budgets because its larger conductor handles the heat load that higher wattage generates in bundled runs.

Fiber Moving to the Edge

Single-mode and multimode fiber are no longer just for backbone runs. High-speed uplinks at 25, 40, and 100 Gbps require fiber at standard distances. The narrowing price gap between single-mode and multimode makes single-mode the sensible default for new installations. EMI-sensitive environments like manufacturing floors and hospitals benefit from fiber immunity that copper cannot provide.

Wireless-First Does Not Mean Less Cabling

The wireless-first approach has not reduced cabling – it has changed what gets cabled. Instead of one drop per desk, you plan for one access point per 30 to 50 users, each receiving a Cat6A run carrying both data and PoE power. Test every horizontal link with a channel test certificate – a Cat6A cable with improper terminations performs worse than well-installed Cat5e.