Some hot shot salesperson comes along and sells the customer, your customer, a new fandangled system that will do everything under the sun and more.
I couldn't agree more Bobby, but in this case, this is not my customer. I'm just trying to help a friend who works for Comcast. This looks like a classic case of; "no good deed goes unpunished" which is why I may back out of the whole mess. When the customer complains about the way it will have to be used, I will get the blame, the complaints, and the lack of payment because it no longer works as it did on the Meridian system!
Larry, just have Comcast install the ATAs and plug single line phones into them. Make sure they work while the tech is there before committing to installing other equipment, because Comcastic will blame any problem on your other equipment.
This has always been my policy when working with Comcast.