A method for setting up a video communication session via an Internet Protocol, IP, network between a first terminal and a second terminal, the method having the steps of: providing a call server on an IP network, said call server configured to facilitate said video communication session between said terminals; registering the first terminal and the second terminal with the call server; assigning a unique identifier to each of said terminals; and characterized in registering said unique identifier and at least one attribute associated with each of said first and second terminals with said call server; said first terminal placing a call through a public switched telephone network, PSTN, to said second terminal to establish a PSTN communication session, and said first terminal simultaneously initiating a set-up procedure for a video communication session by sending a request to said call server to determine whether said second terminal is registered with said call server; and querying, by the call server, a computer readable medium or database associated with the call server and receiving confirmation that the second terminal is registered and has the assigned unique identifier; determining, by the call server, that said second terminal is compatible with said first terminal based on the at least one attribute associated with each of the first and second terminals; assigning, by the call server, a unique video communication session identifier associated with each of said unique identifiers to establish said video communication session; sending, by the call server, a video communication session invitation to said second terminal via said IP network; and when said second terminal accepts said invitation, establishing said video communication session via said IP network between said first terminal and said second terminal, wherein said video communication session is established via said call server. providing a call server on an IP network, said call server configured to facilitate said video communication session between said terminals; registering the first terminal and the second terminal with the call server; assigning a unique identifier to each of said terminals; and characterized in registering said unique identifier and at least one attribute associated with each of said first and second terminals with said call server; said first terminal placing a call through a public switched telephone network, PSTN, to said second terminal to establish a PSTN communication session, and said first terminal simultaneously initiating a set-up procedure for a video communication session by sending a request to said call server to determine whether said second terminal is registered with said call server; and querying, by the call server, a computer readable medium or database associated with the call server and receiving confirmation that the second terminal is registered and has the assigned unique identifier; determining, by the call server, that said second terminal is compatible with said first terminal based on the at least one attribute associated with each of the first and second terminals; assigning, by the call server, a unique video communication session identifier associated with each of said unique identifiers to establish said video communication session; sending, by the call server, a video communication session invitation to said second terminal via said IP network; and when said second terminal accepts said invitation, establishing said video communication session via said IP network between said first terminal and said second terminal, wherein said video communication session is established via said call server.