More AT&T BS
24Mb is the theoretical limit of "Uverse." UVerse is not fiber to the home... it's Ethernet based DSL as opposed to the ATM protocol they used to use and it still runs on copper. They gave it a shiny new name but it's still the same lump it always was.
If you're sitting on top of the DSLAM (DSL Access Multiplier) the system is capable of 36Mbps. Of that there are 2 HD channels (5Mb each) plus 2 SD channels (1Mb each). Point-0 is reserved for voice. The remainder, up to 24Mb, is your Internet. In the future they may bond 2 together to give you "up to" 48Mb but this isn't fiber to the home. They're just putting an F2 (local DSLAM) in the utility closet of the building and running fiber there.
Weird, FTTC/N here in the UK runs up to 76Mb down and 19Mb up over VDSL 2 and a single copper pair and VDSL 2 profile 17a.
In Japan, amongst others, where the DSLAM is in the utility closet of the building, FTTB, up to 100Mb symmetrical has been delivered via VDSL 2 profile 30a.