RIM Question

[Gelf]

ADSL request denied because line was on a RIM. The line I tried was put in several years after I moved in here though (1995-96), and I do remember when I used dial-up on that I could never connect higher than 33.6 (in fact 28.8 was the speed I got most of the time). I remember reading somewhere this was a sign of being on a RIM, is this true? If so, I do have two other phone lines here which connect at faster speeds that I'm giving a go right now.