The folks at Yealink specialize in Session Initiation Protocol phone technology and products, and the IP Video Phone VP530 is a good example of an expandable business-grade phone with a plethora of conferencing features. The VP530 has a 7-inch digital LCD touchscreen that supports resolutions of up to 800 x 480, a rotatable, two-megapixel camera; picture-in-picture video; full video conferencing functionality; integrated high-definition voice with voice activity detection; and 18 one-touch direct station select, or DSS, keys. You also get four VoIP accounts for video and voice calls.
The VP530 phone includes 2 RJ-45 Ethernet 10/100 Mbps ports for network connectivity, one USB port and an SD card slot.
More resources on video phones
Video phones offer low-cost conferencing.
Video tutorial: How to add video to your UC architecture.
How to prepare your network for video sharing.