T568a vs. T568b: What’s the Difference?

T568a vs. T568b

T568a vs. T568b: What’s the Difference?

Key Points

  • T568a and T568b are termination specifications for standard ethernet cabling.
  • There is no functional difference in capabilities between T568a and T568b.
  • T568b is the more modern standard and is commonly used in new organizations and businesses.
  • Both T568a and T568b are backward compatible with older network cabling standards.
  • Unless there is an organizational standard in place, it is recommended to use T568b.

Computer networking is rife with standards and specifications. Among the many debates around best practices, T568a vs. T568b might be one of the harder ones to point toward a definite answer. Both are termination specifications for standard Ethernet cabling.

In practice, there could be zero effective difference between the two in common usage. Now, if your organization or workplace is a little more laidback, you might not even know which standard you are using.

As to which is the better choice to use for your cabling at home, that really just comes down to user preference. It is a subject worth exploring, and one with some clear answers as to what modern businesses and organizations expect in terms of wiring standards.

T568a vs. T568b: Side-by-Side Comparison

Wiring SchemeGreen Striped, Green, Orange Striped, Blue, Blue Striped, Orange, Brown Striped, BrownOrange Striped, Orange, Green Striped, Blue, Blue Striped, Green, Brown Striped, Brown
Commonly Used ForTerminating endpoints of networking cablingTerminating endpoints of network compatibility
Backwards CompatibilityCrossover cable needed for communicating with T568b wiringCrossover cable needed for communicating with T568a wiring
Number of ConductorsEightEight
Intended CableRJ-45RJ-45
Conductor TypesTwisted pair or shielded twisted pairTwisted pair or shielded twisted pair

These two wiring standards are very similar. This should come as no surprise given that they are iterations of the same general standard.

T568a vs. T568b: What’s the Difference?

t568a vs. t568b
T568b is the standard wiring specification for modern cabling.


At the core of this all, there isn’t really a functional difference in regard to capabilities provided by either of these wiring standards. When it comes to wiring up new organizations and businesses, you’ll likely be using the T568b standard.

There isn’t an inherent advantage to using this standard. However, using this standard allows businesses and networking experts to maintain continuity for all cabling. Sticking to one standard also can cut down on the work needed to establish wiring if creating custom cables.

As you’ll see throughout this shootout, there really isn’t an inherent difference between the two in practical usage. Termination points on cabling have no bearing on speed, signal clarity, or any of the other specs you might care about.

Instead, it really does come down to whether you’re in an older organization or a newer one. If you’re looking to implement standard cabling in a new place, you will be using T568b more than likely.

Wiring Differences

Both T568a and T568b use twisted pair conductors within the termination point. Twisted pair cabling is standard across the board for all networking cabling using copper as the primary transmission media.

If you were to split a standard CAT5 or CAT5e ethernet cable along the side, you’d side a bundle of an assortment of individual wires as the termination point. These are color-coded to fit with network specifications and standards.

If you were to create a T568a termination point, the conductors would be arranged completely differently from the T568b. T568b more closely resembles the conductor assembly of the AT&T 258a wiring specification.

T568b is more future-proofed and is the current wiring specification for any new network cabling used in modern businesses and organizations.


Both T568a and T568b are backward compatible with wiring standards more commonly seen with RJ11 network cabling terminator points. This is also true of other network cabling standards of yesteryear, which all adhere to the USOC wiring specification.

T568a communicating with T568b is a bit more complicated, however. T568a and T568b don’t natively communicate with each other. You cannot connect a network device utilizing T568a endpoints to a computer utilizing T568b terminators.

You can, however, connect both disparate connections through the usage of a crossover cable. This is a fairly simple device to create, as it is essentially a standard ethernet cable with a T568a connector on one end and a T568b on the other end.

Crossover cables and patch cables should be common practices for any network engineer working for your business.

T568a may still be the overwhelming wiring standard of choice for older businesses. So, you might have to take the time to create some crossover cables for the sake of connections between devices.

Use Cases

Both T568a and T568b have the same overall goal. One is inherently stronger than the other when it comes to connection speed or strength. Instead, both are used for wiring up RJ45 connectors. You’ll find they can use the same exact copper cabling and connect to the same devices.

Typically, you’ll be using either interchangeably. If you’re connecting devices with ethernet cabling, it will use one of these two standards. Chances are if you’re purchasing new cables for your business, it using the T568a standard.

If you’re in a network closet that has been around for 20 to 30 years, you might come across T568a termination points. Network engineers working for the government are also likely to encounter T568a endpoint connectors.

This is due to the government requiring departments and federal contract workers to adhere to a single cabling standard. As such, T568a is specified as the endpoint connector of choice.

In fact, unless your business has a slew of fiber optic cabling for connecting local network devices, it is using either one of these specifications.

Which Should You Use?

t568a vs. t568b
Both T568a and T568b standards use twisted wire cabling.

©Valentyn Volkov/Shutterstock.com

Unless there is an organizational standard in place, you should opt for T568b. T568b is the more modern standard and is going to be integrated into copper cabling for years to come.

T568a is still perfectly usable, and any networking engineer is going to be familiar with creating termination points using it. Unless there is an overwhelming need or desire to stick with the older specification, you might as well use T568b.

They take roughly the same time to create the termination points. You’re still using the same pairs of conductors. The only real change is in the arrangement of the conductors. If you’re already taking the time to create custom endpoints, you might as well go with T568b.

To keep it short, just stick with T568b unless you have existing specifications that call for the T568a connectors exclusively.

T568a vs. T568b: 6 Must-Know Facts

  1. The T568a is backward compatible with two USOC wiring standards.
  2. The T568a is required for usage by government and federal contract organizations.
  3. The T568a is not as widely used as the newer standard.
  4. The T568b is the more common means of terminating copper ethernet cabling.
  5. The T568b is backward compatible with AT&T 258a wiring specifications.
  6. The T568b is USOC backward compatible with one wiring standard.

T568a vs. T568b: Which One Wins? Which One Should You Choose?

When it comes down to T568a vs. T568b, there is only one real clear winner. The T568b is the cable terminator of choice for most of the world. You will run into organizations or businesses that use the older T568a standard, however.

In practice, they’re functionally identical and it really just will come down to user preference. For any user looking to do some DIY cabling at home, there isn’t a real difference in terms of performance.

As previously stated, both wiring standards use the same exact conductors to wire things up. The only difference is in the arrangement of the conductors. Realistically, you or a network engineer are going to spend the same exact amount of time putting together either termination point.

If you’re looking toward the future and how it might impact your network infrastructure, then choose the T568b. If you’re at a workplace that requires it, stick with the T568a. Both are widely taught and should be understood by anyone splicing together wires for your connectivity needs.

Frequently Asked Questions

Does the endpoint connector have any bearing on speed?

No, the actual transmission media is more what determines the speed of a connection.

Is wiring a T568b connector more difficult than a T568a?

Not at all. The only difference is the arrangement of the conductors in the endpoint.

Can I use T568b with fiber optic connections?

If you’re using copper cabling as the ethernet medium, yes. If you’re using fiber optic cabling as the ethernet medium it has its own set of endpoint connections.

Is T568a better than T568b?

No, both have identical functionality. If you’re concerned about backward compatibility with legacy devices, then T568a has a bit of an edge.

Should I use T568b in my home?

If you’re using pre-made cabling, you’re likely already using T568b.

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