Snom M9 Complete Set (consists of base + 1 handset in the box). Interference-free telephony. 100+ hours standby time. High interoperability . Voice encryption. Security (TLS, SRTP, preinstalled X.509 certificate). Colour Picture Caller-ID. IPv6 ready. Up to 9 handsets per base station. Up to 4 simultaneous calls per base station . Intercom, alarm and calendar function . Voice encryption