Voip the ericsson 4422 ip office system telephone will work with any ericsson system that has ip capabilities it wonrsquot work on a standard telephone line or traditional telephone system extension this is because it needs to be connected to a network and allocated its own ip address feature rich system phone the ericsson 4422 ip office system telephone also comes with an abundance of features making life much easier for the user it has an lcd screen so you can see what