The 2N Uni - 1 Button with pictograms (9153101P) is a SIP Intercom which provides a cost effective solution for access control and communication. It offers full-duplex audio with echo cancellation, integrated relay for door entry systems. 2N Helios IP Uni 1 button 9153101 is ideal for schools, parking lots, shopping malls, hospitals or public buildings. It can be used as an information/emergency help point or as a door entry system.