Abstract: A method of setting up multimedia calls from a telephone terminal (T1) to a terminal (T2) connected to an IP network. The terminal (T1) sends to a server (SMR) a call request (DA) containing an identifier (ID2) for the terminal (T2). The server (SMR) stores the identifier (ID2) in a table (TC) in association with a number (NT) and instigates the transmission by the terminal (T1) of an incoming call (AE) to a number (NS) connecting through to a call set-up gateway (PEA), the incoming call (AE) including a characteristic (CAR) for indicating a relationship between the numbers (NT) and (NS). The call set-up gateway (PEA) signals the characteristic (CAR) to the server (SMR), which determines the identifier (ID2) associated in the table (TC) with the corresponding number (NT) of the characteristic (CAR) to set up the call between the terminals (T1, T2).