Would also say that you should get a "DSL safe" Butt-set, regular ones will drop the DSL signal, and / or damage equipment.
Then get ready to spend big bucks! The Harris's that we have are almost $500 each. We have some others that just "lock out" and beep when connected to an ADSL line. Big PITA. Not real good when you need to identify that line and you can't draw dial tone.
DSL lines shouldn't really be that kind of an issue in residential and small commercial anyway. We often go into terminals and cross connects with 100's of lines and have no idea what each line is but in residential there is only one or two and you should know what they are.
It's also no big deal if you do clip a regular butt set across an ADSL line. Yup, you will interrupt the connection but it will recover. If you want to be safe and save a lot of money just use a DSL filter with your butt set.
-Hal
