Telephone lines have a frequency response from 300Hz to 3kHz.
No. That frequency response is filtered from the cable, to grant a good transmission quality on long distances in analogue mode. In fact, 300Hz - 3 KHz it's the frequency range when the human speech is enough clear to be understandable. ADSL on copper lines works because the signal is using frequencies > 3 KHz, and distance to the DSLAM matters. Nearer you are from it, better your ADSL speeds. In fact, a copper cable can have a frequency response in MHz.
Huh? My iMac has a quad-core i7 CPU and 16 GB RAM.
Theory is gray, but the golden tree of life is green. -- Goethe