Snom M9 Enhancement Set (Extra handset). Interference-free telephony. 100+ hours standby time. Proven interoperability. Security (TLS, SRTP, pre-installed X.509 certifi cate). Color Picture Caller-ID. IPv6 support. Up to 9 handsets per base station. Up to 4 simultaneous calls per base station. Intercom, alarm and calendar function. And much more. Voice encryption