“Extension” - is the extension of the telephone line (PBX) or the Centrex system. It works as an association and allows calling to certain telephone sets without the necessity of dialing the telephone number, but only by dialing a short combination of digits, reaching the desired subscriber.
VoIP Terminations and Hosted VoIP Switch Partition : VoIP Reselller, VoIP Callshop, VoIP Calling Cards, VoIP Callback, VoIP PC-To-Phone, VoIP Device-To-Phone, DID, E-Commerce, etc.