I have four (3 cordless, 1 wired) phones on my existing Verizon old school land line. I pay about 30 bucks a month for bare bones service, calls are crisp even though Verizon keep bugging me to swith to fiber optic. There is a Verizon box on the back of my house that I can get into. I'm thinking of switching to VOIPo if I can do it seemlessy and painlessly. I want to keep my same number. I have high speed internet, (Comcast). What will I need to do to keep using all of my phones with VOIPo?