Yealink IP phones can connect to the Internet if there is Ozeki Phone System XE is available for them.
Open this page: http://www.ozekiphone.com/yealink-t20p-t22p-t26p-t28p-476.html
Yealink IP phones are sold in great quality. These devices have large display screens, provide excellent sound quality and a very simple user interface. These phones can call other VoIP phones through Ozeki Phone System XE of course.
It is easy to connect IP phones to Ozeki Phone System XE. You only need the cables and a simple registration to the system. With a few clicks, all your Yealink phones can be connected to your great quality telecommunication system.