better the complex operation of any computer system. I always like it when I explain something try to find a real life example of clear and simple and that anyone can rely and in this case I will use the telephone network, such that bassa pole in phone booths, in switchboards and in many other devices, wired and wireless enabling hundreds of millions of terminals to establish communication and share information around the world as a computer network that operates in many cases even through own telephone network (ADSL line). We start with an infrastructure that envuleve the world as if it were a fishing net through which establishes the exchange of information but to see some points that must be taken into account and I’ll try to do with similarities between telephone network and computer network. 1. We need a transmitter / receiver and a transmitter / receiver for communication can be established capable of translating the information to to be useful: Red and telephony: A person Computer network: A computer system, PC, server, PDA 2. We need a device capable of sending and receiving information through compatible with the TRANSMISSION and receiver / transmitter: Net telephony: phone terminal as a mobile phone or computer network: A network device as a network card, a modem or other device: 3. A means by which to communicate: Network & Telephony: Computer network cables or air: Cables or air With this we have everything in order to establish communication but.