The SIP-T43U IP phone is a feature-rich business tool for excellent communications and extended functionality. It is a 12-line IP phone that comes with a 3.7-inch large black-and-white screen and the EXP43 support. United Yealink Optima HD Voice technology and wideband codec of Opus, the T43U awards you the superb audio quality and crystal-clear voice communications. Expansion module support Dual USB ports.