D20/D21 is a dual 100Mbps Ethernet port IP phone with 6 SIP accounts, 2 linekeys, and full-view backlit greyscale display. It is a cost-effective IP phone specially designed for office staff. It supports IPV6 & IPV4 and ATCOM cloud network management platform, with full "user, network, deployment, security" features, good IP PBX and network compatibility. It is suitable for enterprise unified communications and IP voice applications of operators. Its innovative multi-scene key mode, which can be used to expand up to 12 visible DSS keys, definitely improves the office productivity. It adds user-friendly help information to the LCD, whichcan reduce the user's learning costs.