Now it is possible to allocate two directions of creation of internets – public and specialized networks. Public networks are the computer networks providing services by everyone for a certain payment. Generally it is services network, and in some cases terminal access. Specialized networks are the academic networks.
teleconferences are a powerful tool of communication between members of a network. Their sense is well looked through in their English name (Echo Conference) that in primitive sense means: at one knot hallooed - at the others responded.
Such car is called as a lock (Gate) between these networks. It is clear, that between two networks there can be some locks (however, can not be absolutely, and then the exchange of messages is not present, or it goes through an intermediate network with which there are locks at both). The lock accepts the message from a network A, copies it in the form taken in a network B and sends through a network B to that car for which it is intended. Unfortunately, time of obtaining the message by the addressee in that case is considerably slowed down, but, as a rule, all the same it occupies shorter interval, than use of services of usual "paper" mail.
In many cases use of wire or fiber-optical communication lines is impossible or economically inexpedient. In this situation one of the most effective solutions of the problem of communication, and often and, use of radio networks of data transmission is unique.