The service often seen at different sites works in such a way that you
need to enter your telephone number in a special window and after some seconds
you and the company representative will receive a call, which will allow you
communicating.
A modern voice communication SIP protocol is widely used to make calls in the Internet. However, the final subscriber is mostly interested not in the very SIP standard but in the SIP telephony conception based on it.
One one hand, all traditional conveniences for making telephone calls, compatibility with the international subscription base and the procedure of dialing numbers are kept.