be compressed any further. Therefore, the true speed is shown. Do DSL filters affect modem performance? Yes. DSL works by sending an "out-of-band" signal on your regular phone line. 56k Modems operate in the normal voice range of a standard phone line ( ~150 - ~3500hz). DSL adds a signal at much higher frequencies. (That's why not everyone can get DSL - if your phone line is long and has load
