T-Mobile has used the color magenta to represent its brand for over a decade, and it's been far from shy about defending the hue from others. Now the carrier has filed its latest color-protecting complaint against AT&T, alleging in a suit on Friday that its competitor's new subsidiary, Aio Wireless, is using its own trademarked color to confuse consumers. "Out of all of the colors in the universe," T-Mobile's complaint reads, "[Aio] chose magenta."

"T-Mobile needs an art lesson."

The complaint draws connections between the launch of Aio, which relies on off-contract plans, and T-Mobile's own switch to off-contract plans, which occurred just months before. "AT&T set up Aio to compete directly with T-Mobile," the complaint reads. It argues that Aio's use of the color magenta "is likely to dilute T-Mobile’s famous magenta color trademark, and to create initial interest confusion." T-Mobile has been using magenta since 2002, but its parent company, Deutsche Telekom, has been using it as far back as the 1990s.

Aio Wireless does use a bright shade of purple, but it's far darker than T-Mobile's hot pink, which it calls magenta. "T-Mobile needs an art lesson," an Aio spokesperson tells The Verge. "Aio doesn't do magenta." T-Mobile includes several images in the complaint to illustrate the confusion it's hoping to prove. Among those are both its own and Aio's coverage maps, which display varying shades of purple across the United States.

Aio Wireless coverage map (left), T-Mobile coverage map (right), as depicted in T-Mobile's complaint.

T-Mobile has previously requested that entities which aren't wireless carriers cease using the color too, including Engadget Mobile back in 2008. Our own Nilay Patel, then writing for Engadget, notes that for such a lawsuit to succeed, T-Mobile would generally have to prove that its own color of magenta was in use, that it was being used in conjunction with a telecommunications product, and that its use could confuse or was intended to deceive consumers.

We've reached out to T-Mobile and AT&T for comment, and we'll update if we hear back. For now, T-Mobile CEO John Legere seemingly has this to say:

Here is the Crayon box that @ATT must have been using :) pic.twitter.com/9SG5b3Ztse — John Legere (@john_legere) August 28, 2013

Update: T-Mobile tells us that AT&T is "trying to get a free ride" from "America's un-carrier" by using magenta, and that it filed the lawsuit to stop its competitor from doing so. T-Mobile's full statement is below.

When consumers see magenta in the wireless world, they think T-Mobile. But AT&T, through its subsidiary Aio Wireless, has been trying to get a free ride from T-Mobile’s success as America’s un-carrier by using magenta in its marketing. We filed this lawsuit to stop them, and to protect T-Mobile’s powerful magenta trademark.