Telecommunication systems should be able to handle different protocols. Thereto, with a first protocol being Internet Protocol v6 using 128-bit addresses of a first kind and with a second protocol being Internet Protocol v4 using 32-bit addresses of a second kind, an access system is provided with a generating section for, in response to an address of one kind, generating a corresponding address of an other kind for a terminal-to-terminal communication and independently of which terminal has initiated said terminal-to-terminal communication. For a set-up phase, a replacing section replaces addresses of a second kind by corresponding addresses of a first kind, and an adding section adds, in addition to addresses of a first kind, corresponding addresses of a second kind, in set-up messages. For a communication phase, activating sections activate translating sections, which translating sections translate addresses of one kind into addresses of an other kind, in packets.