Up to 20 SIP accounts per system; up to 20 lines per handset DECT authentication & encryption technology to protect calls & account 3-way audio conferencing for easy conference calls Supports Push-to-Talk Automated provisioning options include TR-069 and XML config files Use with Grandstream?s UCM series of IP PBXs for Zero Config provisioning HD audio to maximize audio quality and clarity; full duplex speakerphone Supports advanced telephony features, including call transfer, call forward, call-waiting, do not disturb, message waiting indication, multi-language prompts, flexible dial plan and more