Remote access points series - ISP connections types.

Hi everyones! I going to buy some remote and travel acces points for offices. Interesting in 14C/21D models. What connections types to the ISP do they use? Static and DHCP addresses - understand. But there is one method of connection is PPPoE. Does remote AP connects to ISP via PPPoE? Because in documentation for 21D http://docs.fortinet.com/d/fortiap-21d-quickstart writes something about PPPoE.