As buildings become more intelligent, relying on technology like building automation and high-performance AV systems, there’s a sector of the industry that believes shielded Category 7 cable is the best way to guard against connectivity issues.
Is that true—is Category 7 worth the investment? When do you really need to use Category 7 or 7A cable instead of Category 6A in smart buildings? Let’s take a closer look.
Do Any Applications Call for Category 7 or 7A Performance?
While Category 6A supports IEEE 10GBASE-T applications, and Category 8 supports 25GBASE-T and 40GBASE-T applications, there are no true IEEE applications for Category 7 or 7A cabling.
Category 7’s 600 MHz performance and Category 7A’s 1000 MHz performance aren’t enough to support 40GBASE-T applications, so the maximum data rate supported by both Category 7 and 7A is 10 Gb/s—which is the same as Category 6A. Because no application requires Category 7 or 7A cabling performance, the Telecommunications Industry Association (TIA) doesn’t recognize or approve these cable types. It’s not a requirement for any Ethernet standard, either; it’s a cabling category created by a group of manufacturers in hopes that it would be needed in the future.
In countries like France and Germany, where shielded cabling is the standard due to strict EMC regulations, you’ll find that Category 7 deployment is more common. It was ratified in 2002 in the ISO/IEC 11801 Standard and meets Class F channel specifications for crosstalk and interference. In 2010, ISO/IEC introduced Class FA channels and Category 7A cabling.
The Important Role of Connectors
We’ve established that no existing Ethernet applications require solely Category 7 or 7A cabling, but there’s another factor at play as well. In order for cables to connect to active equipment, active equipment manufacturers must design their products with ports that can accommodate the right types of connectors.
Because Category 7 and 7A cables aren’t recognized or needed, today’s Ethernet equipment and devices (everything from routers and switches to surveillance cameras and access points) don’t have ports to accommodate Category 7 connectors. Instead, active equipment relies on the RJ45 Ethernet connection interface and supports RJ45 connectors. (Interesting side note: The frequencies that allow Category 7 and 7A cabling to reach higher speeds aren’t required by Ethernet equipment either.)
While Category 7 connectors are available to terminate Category 7 cable, they utilize a non-RJ connection interface. These connectors can’t be used to connect any of today’s Ethernet equipment or devices, which renders Category 7 cable unnecessary—and here’s why.
To connect a Category 7 or 7A cable to Ethernet equipment and devices, the only option is to terminate an RJ45 jack onto the cable instead. This solves the connectivity problem, but it’s important to note that this downgrades the entire system. A Category 7 cable terminated with a Category 6 or 6A connector is no longer a Category 7 (Class F) system—it’s a Category 6 or 6A system (depending on which connector is used). Category 6A satisfies every application that Category 7 can support, so the reasons for deploying Category 7 or 7A cable quickly fade.
The performance of your system will always default to the lowest Category level deployed in that system. For example, if you use Category 5e cable and terminate it using Category 6 connectors, then you have a Category 5e system.
When will you use Category 7 or 7A?
Let’s ask this question again: When do you need to use Category 7 or 7A cable? The answer: For Ethernet applications, probably never. There’s no need to over-specify and pay more for a cable that doesn’t provide better results. If you need Category 7 or 7A performance, then there’s good news: Category 6A works just as well—and at a lower cost.
If someone tells you that Category 7 or 7A cabling is absolutely necessary for a specific application, then they likely need a shielded system, which is also available in a Category 6A system (and ensures that you don’t pay a higher price than necessary).
We’re here to answer your questions about Category 6A, 7, 7A and 8 cable for your next project. As your trusted advisor, Belden’s goal is to make sure you get the most from your cabling investment—without overspending on a system that won’t provide what you need or expect.
Adapted from Putting a Spoiler on a Pinto: Is Category 7 Cable Worth it in Smart Buildings? (belden.com) by Ron Tellas of Belden.
