Siemens Enterprise OpenStage 40 SIP IP-phone is a great solution for people working in the permanent place. This model features a large display and easy setup of various protocols such as TDM, HFA and SIP.
VoIPCall is a Minneapolis based Internet Telephony Service Provider [ITSP] that provides a first class Voice Over IP calling service designed for business customers, Telcos, ISPs and government entities around the world.