Part of our Back to the Basics Series. See also: PSTN, SIP Trunking, and Telephony.
It turns out there is more than one way to skin a cat.
Thereís no need to call the SPCA. No one is actually skinning cats here.
Not too long ago there werenít a whole lot of options for making phone calls. That has all changed today. If youíre wondering what Voice over Internet Protocol (VoIP) telephony is, how it differs from the public switched telephone network (PSTN), what pieces make VoIP work, and what some of the advantages of VoIP are then put your feet up and read on.
PSTN vs. VoIP
VoIP provides an alternative method for making phone calls than the PSTN. The crucial distinction between how these differing systems accomplish the task of transmitting information is in the type of switching employed.
The PSTN uses circuit-switching technology. In other words, the PSTN opens up a direct connection between two subscriber lines that allows the system to send and receive information from each party in real time. A new connection is established with every phone call made and is closed when the phone is hung up.
VoIP, however, uses packet-switching technology. The nitty gritty of how this process works is addressed below, but at a high level, the voice audio is digitized and broken up into little pieces called packets that are sent over the internet and follow the path(s) of least resistance to the other end. Once the packets reach their destination they are reassembled in the correct order and played back as audio.