Skype Security Overview – Rev 1.5- 3/12/05

All telephone systems in the world use a microphone to turn sound waves into an electrical signals and a speaker to turn electrical signals back into sound waves at the other end. But the techniques used for connecting microphones and speakers has seen considerable development over the past one and a quarter centuries. Early systems connected the microphone directly to the speaker using a copper wire. In the 1970s AT&T deployed the first systems that could transmit multiple phone calls over a single wire by converting each phone call into a stream of digital data. VoIP systems continue this evolution by taking independent digital streams, compressing them, breaking the streams into packets, and sending those packets over the Internet. Naturally, the process is reversed at the receiving end.