Apple said to limit wireless speeds on some U.S. carriers

Editor's note: See update at the bottom of this post.

A developer who provides iPhone hacks claims to have discovered code in iOS that suggests Apple is helping the top three U.S. wireless carriers throttle data speeds for all iPhone and iPad customers.

Joseph Brown, operator of the Web site iTweakiOS, claimed -- in a post that has since been taken down -- to have discovered code on iPhones and iPads operating on Verizon, AT&T, and Sprint that effectively caps the data speeds that can be achieved on the carriers' networks. Brown took snapshots of the code, which he said specifically limits the iPhone 5 on AT&T to considerably slower wireless data speeds than the device is capable of reaching.

Brown called the code proof that AT&T was hamstringing the data speeds for iPhone and iPad users on its network:

Yes folks, this is throttling coding. When we made the AT&T Hacked Carrier Update, this was the first line of coding to be scrapped when the project started. Immediately, through my testing on an AT&T iPhone 5 and iPad 4th generation, there were significant and noticeable results.

As for the nation's biggest carrier, Brown said he found code that Verizon was limiting data speeds on its 4G LTE network. While noting that the 4G limitation did not appear to extend to Sprint's high-speed network, Brown did say he found code that prevents the iPhone 5 on Sprint's 3G network from achieving the faster EVDO 3G speeds.

Brown said T-Mobile, the smallest of the top four wireless carriers, appeared unaffected by the code because it operates on different frequencies for HSPA+ and LTE.

Brown suggests that because Apple controls the operating systems on its devices, the code may have been inserted at the behest of the carriers.

"From previous statements released by AT&T and many tech orginizations [sic], iPhones are very complex devices with a very complex OS," Brown wrote in his report. "The OS eats much more data, even when in idle mode, than most phones on the market. So by carrier request, Apple limits devices to 'even out' the network, even if it means Galaxy users out perform Apple devices by such large scales."

That is a claim denied by two carriers contacted by CNET.

"We do not throttle," Verizon representative Brenda Rainey told CNET, noting that the carrier will temporarily manage data usage of high-volume 3G data users when they are connected to a congested cell site. As far as the code goes, she said she could offer no comment "For that, you would have to call Apple."

Sprint also denied throttling data speeds on any postpaid devices. Apple declined to comment on the report, and AT&T did not respond to request for comment.

Update, June 6 at 1:10 p.m. PT: Adds that iTweakiOS has since taken the post down without explanation. Brian Klug over at AnandTech has put together a detailed explainer that pokes holes in Brown's idea, adding that throttling is "not the case currently with any iOS devices."