yes you should be able to do that, but your local phone company might hassle you over it. Here’s an internet post I found that might help as well: http://www.dslreports.com/shownews/How-to-Get-2399-ATT-Dry-Loop-DSL-87863
Yes you need a landline for DSL service but no you should not need to actually have landline voice service. The two do run over different parts of the circuit. I believe the industry term for what you seek is “dry loop” — in this case, DSL without voice. But before you cancel your voice line, I caution you to consider another advantage of keeping your voice service … 911. I’m a big fan of landline phone service, both for the superior voice quality, but also because of the technology behind 911. If you or your family were to ever have an emergency that required dialing 911, personally I’d rather do it from a landline phone, than a cell phone. From a landline, the 911 operator instantly knows the address from which you are calling from. This is not typically the case from a cell phone although that technology is supposedly coming down the pike. Also, 911 from your landline routes to your local emergency agency (local fire or police station, typically). Cellular 911 is either answered by specially trained personnel of the cell phone company, or routed (more commonly) to the State Police of Highway Patrol. (For my area, for example, that Highway Patrol office is more than 20 miles away!) The dispatcher then has to figure out where you are, what you need, and transfer your call to the appropriate local agency closest to your location. This can sometimes take a significant amount of time. I no longer dial 911 from my cell phone unless I have no other options. Instead I now dial the agency I need directly. (Yes I store them as speed dial numbers in my cell phone!) In my opinion, cellular 911 just doesn’t measure up to landline 911. So dialing 911 from a landline is ALWAYS the best option.
Here’s a writeup I did for my hiking group 3 years ago related to this:
http://hiking.bondon.com/FAQMain.cfm?page=Msg&Email=110
So, in your case, if you decide to keep your landline for at least receiving calls and as an insurance policy should you need to call 911, my suggestion is to switch to measured rate service (cheaper than flat rate if you don’t make too many local phone calls). AND think about getting rid of long distance service on the line as well so you’re not paying the $5/mo interconnect fee and associated taxes that go with it. Then you’re monthly phone bill should be less than $10/mo, including taxes and fees (probably under $5/mo if you qualify for Universal Lifeline Phone service.)
But if you do decide to get rid of your landline, I suggest you program in your local police and fire numbers into all your cell phones and train your family to phone them direct. Believe me, you’ll get thru MUCH faster!