Thanks for the reply.
The reason I was looking into a tester for DSL was because of a situation I encountered last week when I was relocating a jack in a customers home.
Apparently, at least according to the customer, Verizon now offers DSL with or without POTS service in our area, depending on whether or not the subscriber wants or needs it. Not sure but I think this is what another poster referred to as "Dry Pair" DSL service.
I was slightly panicked at first thinking I had downed the service because when I connected my TS21A, and went off-hook, I couldn’t draw dial tone. You get the distinct click of the line being seized but then just dead silence. I was glad that when the wireless hub/modem and laptop were again connected, the DSL service came back up almost instantly and functioned nicely.
For the time being though, I won’t be purchasing any expensive specialized test equipment for this purpose.