Can I port a phone number with DSL on the line?

Technically, yes... 

The Telephone Number will port. Even if the donor carrier approves the port with DSL still included, the porting process will not allow the DSL feature to remain on the line.

Many providers of DSL (including Sprint) will deliver a residential DSL internet service and the customer’s home phone number over the same copper wires. This effectively means the customer’s phone number is tied to their DSL line.

Therefore, if you port their phone number to our network – their DSL service gets automatically cancelled as well.

In this case, the only way to successfully port the number is to order new DSL service (which will come with a new phone number) and once that service is installed and tested, then you can port the old number and the old DSL service will be cancelled without interrupting internet service.