The older telephone function on the basis of analog signals. We can send analog signal to other computer and to get signal to our computer we must convert analog signal to digital signal. And now we have a device which can convert the signals both. It is a MODEM. MODEM have got two serves. The first is a Modulator (converts digital to analog) and the second DEModulator (converts analog to digital).
The Internet is a huge network of computers spanning this planet and is now started to bring in the surrounding area like space. Some computers like servers share data, others just surf the web as clients downloading the data. Public Internet began in the late 70's. In the 70*s web users used an interface called telnet, but now that program is mainly obsolete. Telnet is most widely deployed in accessing college email accounts.The Internet is very helpful, because it's a huge database of knowledge, from the pictures of family trips to an analysis of quantum mechanics.