What does a good DSL waveform (signal) look like?

Does anyone know what a clean SHDSL signal should look like on an oscilloscope? We are using two Westermo DDW-120 Ethernet Extenders and they seem to be resetting. I think induced noise on the copper pair between the two extenders is causing a problem. The extenders are dropping out. Does anyone have a reference picture of the DAL signal and/or any information on characteristics of a dsl signal.
Thanks!