TP-Link beta firmwares usually have the sh telnet command enabled to get to a shell. Then you can use the commands:
/firmware/dsl_cpe_pipe.sh lfcg 0
/firmware/dsl_cpe_pipe.sh lfcg 1
/firmware/dsl_cpe_pipe.sh lfsg 0
/firmware/dsl_cpe_pipe.sh lfsg 1
0 = upstream and 1 = downstream for those commands. lfcg = LineFeatureConfigGet which shows what's enabled on the TP-Link itself, lfsg = LineFeatureStatusGet which shows what's in use, subject to cabinet capability and the DLM enabling retransmission for your line.
TP-Link release firmwares don't give shell access, although there is a
way around that.