On paper the gap is 250 MHz against 600 MHz. In a building, the number that decides whether Cat7 is usable for you is not a frequency at all — it is the connector on the end.
Figure 1: S/FTP individual foil pairs and overall braid in Category 7 infrastructure.Quick answer
| Cat6 | Cat7 |
|---|
Bandwidth | 250 MHz | 600 MHz |
|---|
ISO/IEC class | E | F |
|---|
TIA category equivalent | Yes | None |
|---|
Specified interface | RJ45 | GG45 or TERA |
|---|
Shielding | Unshielded or overall foil | Pair and overall |
|---|
1G to 100 m | Yes | Yes |
|---|
10GBASE-T | 55 m | 100 m |
|---|
Listed in the current TIA-568.2-D | Yes | No |
|---|
Practical term of art | Standard RJ45 ecosystem | Proprietary connector ecosystem |
|---|
The connector is the argument
Cat6 is an RJ45 cable. Cat7 is not. It is specified around interfaces that go by the names GG45 and TERA, and neither of those is RJ45.
GG45 was designed so that an ordinary RJ45 plug can still be inserted for backward compatibility, with the extra contact pair brought into play when a matching plug is fitted. TERA is a different design and is not RJ45-compatible at all. Either way, the practical consequence is the same: a Cat7 channel is not plug-and-play with the rest of the building.
That matters more than it sounds. When Cat7 cable is supplied and then terminated with ordinary RJ45 plugs — which happens routinely — the result is not a Cat7 link. The connector is part of the channel, and a channel performs to its weakest component. You have paid Cat7 prices for a link that certifies as something lower.
Where the extra bandwidth would actually go
600 MHz against 250 MHz is a real number, but ask what it buys. 10GBASE-T is satisfied at 500 MHz, which is Cat6A. Cat7’s additional 100 MHz above that does not open up a new Ethernet rate — the next step up, 25GBASE-T and 40GBASE-T, is specified over Cat8 at a 30-meter channel.
So Cat7’s honest advantage over Cat6 is the same one Cat6A has: 10GBASE-T across the full 100-meter channel. What Cat6A adds on top is that both ends of the link are RJ45.
Why the category exists at all
Cat7 comes from the ISO/IEC side of cabling, where Class F is a recognized grade, and it is widely specified in European tenders that are written around ISO classes rather than TIA categories. In a building designed end to end for it — GG45 or TERA patch panels, matching outlets, matching patch leads, installers who work with the system regularly — Cat7 is a coherent choice and it delivers what the class promises.
The trouble is the middle case: a project that specifies Cat7 cable because the number looks better, then terminates it into an RJ45 infrastructure because that is what the rest of the building uses. That combination does not produce a Class F channel. It produces an expensive Class E or EA channel.
What most projects should specify instead
Cat6A. It reaches 10GBASE-T over the full 100-meter channel, uses the same RJ45 interface as everything else on the site, certifies with the same testers, and has several suppliers competing on price. The case for Cat7 only holds where the whole channel — cable, panels, outlets, cords and the installation crew — is built around the matching interface.
If the requirement is genuinely 25G or 40G over short runs, the answer is not Cat7 either. That is Cat8 territory, and it comes with its own 30-meter limit.
What Cat6 gives up if you move to Cat7
Two things, and both are practical rather than electrical.
Interchangeability. Every RJ45 lead, coupler, patch panel and laptop in the building is built around the same interface. Introducing a second interface type means a spare-parts library, a different termination tool, and a rule that somebody has to remember. Sites that run two connector systems run them badly.
Test and certification. Category certification is done with a field tester and a matching adapter set. A Cat7 channel needs adapters and limits that not every tester on the market carries, and a channel that cannot be certified has to be argued about instead of accepted.
Cost, in three places. The cable, the connectors, and the labor. The third is the largest and the least visible line in a quote. A termination system an installer has never used takes longer, and that time goes on the invoice even when the cable price looks competitive.
Shielding practice comes with it. Cat7 is a pair-shielded, overall-shielded construction. The shield has to be bonded to ground at the terminations to do anything, and bonding is a skill. An unshielded installation carries no such requirement and offers no way to get it wrong.
Field scenarios
A new office in Frankfurt, tender written in ISO classes, Class F specified throughout. Coherent, as long as the whole channel is Class F. Verify the patch panels and cords carry the same class, not just the cable.
A US office where the integrator proposes "Cat7 for future-proofing". Ask which interface is being used for termination, and what the channels will certify as. If the answer is RJ45, specify Cat6A and keep the money.
A warehouse with a 130-meter run to a far corner. Cat7 is not the answer here despite the 600 MHz figure — the 100-meter channel limit applies to every copper category. This run needs fiber or an intermediate switch.
FAQ
Is Cat7 better than Cat6?
On specified bandwidth, yes — 600 MHz against 250 MHz. In practice the advantage over Cat6A is close to nil, and Cat7 costs you a non-standard connector ecosystem.
Can I plug an RJ45 into Cat7?
Into a GG45 socket, yes, with backward compatibility. Into TERA, no. And an RJ45-terminated Cat7 cable is not a Cat7 channel.
Does Cat7 support 40 Gigabit?
No. 25GBASE-T and 40GBASE-T are specified over Cat8 at a 30-meter channel.
Is Cat7 recognized by TIA?
No. TIA-568.2-D lists Cat5e, 6, 6A, 8.1 and 8.2. Class F exists in ISO/IEC 11801, and Cat7 is an ISO-side designation.
Should I use Cat7 in a data center?
Only if the whole channel is built for it. For switch-to-switch links inside a rack row, Cat8 is the specified product; for everything else, Cat6A.
What about Cat7A?
Class FA runs to 1 GHz and is specified with the same non-RJ45 interfaces. It has the same ecosystem problem, one step further up.
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