DSL stands for digital subscriber line. It is a high speed internet service that runs to the user via an ordinary phone line, although it is not analog, not dial-up, and not voice.
Up until 2009, Bellsouth required users to have a voice line first, in order to subscribe to DSL service. For many Boca users, this was an annoying requirement. If you just wanted to pay for a cellphone and for DSL, you couldn't.
Now, you can get "naked DSL"; that is, pay just for your DSL service and nothing else. This is what we have, and it works great! In addition, we use the magic jack ($20 a year for unlimited calling in the US). This is much cheaper than vonage, Comcast Cable's Voice Service, or an AT&T voice line.
In short, DSL, at the rate available, without the voice line, is your best deal. Add a Magic Jack and you are set!