AT&T Secretly Throttling their Smartphone Customers (Video)

March 1, 2012 in Demos, News, Video by Hashim Fannin


AT&T has made it no secret they are short on spectrum.  In response to their spectrum shortage AT&T has made a number of changes.  They’ve changed their data plan offerings and have even instituted the throttling of data speeds on unlimited customers once they hit a certain point of data usage.  However, there is one change AT&T made that they didn’t tell you about.  AT&T is now throttling all smartphone customer’s data speeds during phone calls.  It doesn’t matter what rate plan you are on, when you are on a phone call, your data speeds will be throttled by the network.  When on a call AT&T slows your data down to approximately 800k-1meg on the download, and a virtually unusable 20-24k on the upload.

We decided to do a series of tests to see where the data speed management was coming from.  We wanted to know if it was being done on the device level or on the network level.  To test this we used an international GSM Unlocked Galaxy Nexus.  When we put a T-Mobile sim card in the phone we got pretty good data speeds at 5.5Mbps download and 2.8Mbps upload when not on a call.  When on a call, we didn’t see much change in the data speeds as we pulled 4.7Mbps download and 1.7Mbps upload.  When we tried the same thing with an AT&T sim card in the same phone, the in-call throttling was quite ostensible.  We went from 4.5Mbps download and 1.1Mbps upload off-call, to 1.0Mbps download and .024 (24k)Mbps upload.  This was using the same phone in the same location, but the only difference being we used an AT&T sim card instead of T-Mobile.  We repeated this same test in several different high signal locations and got the same type of results every time.

We then spread the test across several other AT&T devices to see if the throttling was device specific.  We found the device you use does not matter (since the throttling is being done at the network level).  We tested the Galaxy Note, Pantech Burst, iPhone 4, iPhone 4S, Motorola Atrix, Motorola Atrix 2, Galaxy S2, Galaxy S2 SkyRocket, and several other AT&T smartphones and still got the same results.  We tried the test with different sim cards for different accounts, we tried different locations, and we still always wound up with the same results, in-call throttling.

We are not sure exactly when AT&T started with the in-call throttling.  We started to notice the difference in in-call speed almost a year ago.  There was a point in time that using the phone while still on a call barely made a difference in data speeds.  A person could surf the web, download apps, send picture messages, upload pictures to Facebook, and other data related activities and not have a problem.  Now trying to upload a picture to Facebook during a call is almost impossible, due to the ridiculously slow upload speeds (24k) you’re throttled to while on a call.  Trying to download apps takes much longer than it should, due to the slowed down data speeds.  Web browsing while on a call is frustratingly slow.  All in all, it’s gotten to a point that unless you’re on wifi, it’s probably best not to use data at all during a call.

The results of our tests clearly show that AT&T is throttling customer’s data speeds during calls.  No matter what device you use or how fast of a data connection you have at the time, when you get on a call your speeds wind up almost the same.  That fact clearly shows this is due to throttling.  Just look at the upload speeds.  There is no explanation for your upload speed going from over 1Mbps, down to .024Mbps just because you’re on a call.  For those that don’t understand what that means, it means you went from a speed of 1,000 down to 24.  To put it in perspective, dial-up internet has a 56k connection.  On the download side of things, it doesn’t matter if you have a 2Mbps connection or a 6Mbps connection, if you get on a call your data speed is going to go down to around 1Mbps.  It doesn’t matter how good of a signal you have, it doesn’t matter what phone you use, it doesn’t matter what plan you’re on, because in the end AT&T is going to secretly throttle you when you’re on a call.


Video Demonstration of AT&T’s Secret Throttling


AT&T’s commercial shows this woman talking and surfing wonderfully…too bad you can’t do that on your phone (since AT&T is going to throttle your speeds).

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