the modem only allow 1 facility whether to use phone or internet but in DSL service we can use both at the same time so then that device in case of DSL is not called modem from the concept. so then is it some kind of amplifier which gives both facility because by modem we can't avail both facilities at the same time.
DSL is technology that allows digital data transfer over a telephone line. Voice data transfer is analogue. There is no channel conflict and that is why you can use both at the same time over the same line. Dave
