babynod :
old phone lines. like in older houses etc? or like....u mean the phone line before it gets to the actual house? sorry this is all new to me
It can be both, some home lines can be low quality some lines from provider to you home can be low quality.
If you live in a big city this problem can be minor since the distance from your house to the phone central can be short, but longer the distance over the country villages, this problem can arise.
You should ask the guy who will install to make a test with the ADSL modem or router, if the ping to the default gateway in your network will be less than 20ms then you will be fine. For example at my current cable provider with 30Mbps connection, i got avg ping of 5ms to the network...