Voip Only Dsl

Is there such a thing as voip only dsl? I would like to transmit voip packets on a voip only network where data packets are not present.

Simply- No

There are any number of centrix style VoIP providers who will supply you with DSL (at least in the UK). Their network may be VoIP-centic and they may even run QoS that favours VoIP, but the shared and contended nature of DSL means others are going to be viewing ebay while you are chatting.

As long as you are running a business grade DSL connection i.e. low contention ratios and Quality of Service, and you don't shove data down your connection or hope to pack it with your own calls (which causes problems on any connection) there shouldn't be a major problem.