A Revolutionary SIP Phone for Enhancing Productivity. The SIP-T46S IP phone is the ultimate communications tool for busy executives and professionals. In addition to offering better overall performance than the T46G, this device has a faster interface with a rich, high-resolution TFT color display. Built with Yealink Optima HD technology and wideband codec of Opus, this device enables crystal clear communications. The SIP-T46S is also built with Gigabit Ethernet technology, for rapid call handling and use with accessories like a Bluetooth USB Dongle and a Wi-Fi USB Dongle. The new T4S series offers the same elegant appearance of the T4 line, but with improvements for greater interoperability and collaboration.