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.
Complete Platform VOIP/SIP Residenctial and business.Reseller programm , and service 4 provider(softphone,accessnumber,callback,az wholesale,webmaster,rent softswitch