FreeSWITCH, a scalable open source cross-platform telephony platform is the world's first of its kind, and was designed to support text, audio and video. For two years it has been working with Yealink, and recently revealed the latest iteration of their efforts. In short, several of Yealnk's ultra-elegant T4 series of IP phones as well as SIP-T21P E2 and the W52P DECT phone.