I have the Arris BGW210 gateway for my fiber internet, and want to connect my existing POTS phones for VoIP

I need to know how many extension phones are supported by this gateway. I currently have 5 extension phones in various rooms of the house, and would like know if the BGW210 will power them all. There are 2 AT&T phones, 2 GE wireless phones via base units, and one old GTE flip style. I don't know what the loads are.