Owning voice equpiment

Hello,

I am doing a new network deployment for a customer of mine who has business internet and business voice (5 lines) through Comcast. I have already recommended to the customer to purchase their own business internet modem and would like to recommend the same for the voice equipment. Is there a recommneded compatibility list of voice equipment I can refer to that I can reference to my customer?

Having not worked with Comcast before on voice it is my understanding that the business class voice has its own equipment providing that service and is not integrated into the modem like the residential service is.

If I am not correct on this could someone please lay out to me how Comcast deploys voice in conjunction with business internet?

Thank you

Sean