Concerning practical implementation, the VoIP gateways have proven to be the best. Many companies are successfully using the IP telephony thanks to its two main characteristics
Decrease in international and long distance call cost expenditures
Stable communications between company’s offices throughout different cities and counties
A leader of innovation and state of the art solutions for Gateways and SIM Server solutions, locally and internationally to all existing networks GSM/CDMA/UMTS/VoIP