While there are many advocates for VoIP telephony, and many lists explaining the benefits of using VoIP rather than PSTN, few take the time to actually delve into what it is and how it works.
In simple terms, VoIP (Voice over Internet Protocol) is the transmission of voice over the digital network, rather than the public switched telephone network (PSTN). By using internet protocol data packets to transfer voice, fax, and other data over the shared network, toll charges can be eliminated, making VoIP cheaper than calls made over PSTN.
Using packet-switched telephony, VoIP carries voice information to its destination in many individual network packets across the Internet. One they have reached their destination, the packets are reassembled and adapted to voice. The following steps are taken to originate a VoIP telephone call:
- Media channel setup
- Analog voice signal is digitized
- Encoding to prevent unauthorized illegal access
- Transmission as Internet Protocol packets over a packet-switched network
On the receiving end, the above steps are repeated in reverse order:
- Receive the IP packets
- Decoding packets
- Converts digital packets to analog, producing the original voice stream
With the use of various protocols determining the type of error checking and data compression methods being used to deliver the message, as well as various codecs encoding and decoding the message, VoIP is a secure way for voice to be transmitted.