Here is the official link directly to this info below. I searched in the Nettalk Forum for the updated info & couldn't find it but I found the link below.
This should save you some time & anyone else who might also benefit from this info in the future: http://faq.nettalk.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=255&ratingconfirm=1. Cheers :)
I am using a Linksys E900 and it's set up as wifi despite my NetTalk Duo being only the basic one. Go to FAQ's and then knowledge base and drill down into the index. It lists the ones that work well with the Duo and the ones that don't work so well.
I am currently using the Verizon FIOS supplied router, but I think any router work with this. I just purchased a new router which will allow me to prioritize certain ports (I think), which will be a good feature since I want voice traffic to be as clear as possible. All in all I'm very happy with this purchase.