Just upgrade AT&T DSL Service to 6Mbps. However, the modern status and broadbandspeed test results show the speed is still 1.5Mbps.
Moderm type: TP-link 8817
ADSL Firmware Version : FwVer:3.11.2.162_TC3086 HwVer:T14.F7_5.0
Line State : Showtime
Modulation : G.DMT
Annex Mode : ANNEX_A
Downstream Upstream
SNR Margin : 6.5 8.0 db
Line Attenuation : 63.0 31.5 db
Data Rate : 1504 64 kbps