Voip Application Notes; Voip Introduction; What Is Voice Over Ip - ZyXEL Communications P-2812HNU-51c Support Notes

P-2812HNU-51C Support Notes

VoIP Application Notes

VoIP Introduction

What is Voice over IP?

Voice over IP refers to communications services — voice, facsimile, and/or
voice-messaging applications — that are transported via the Internet, rather than the
public switched telephone network (PSTN). The basic steps involved in initiating an
Internet telephone call are conversion of the analog voice signal to digital format and
compression/translation of the signal into Internet protocol (IP) packets for
transmission over the Internet.
It is becoming increasingly common for telecommunications providers to use VoIP
telephony over dedicated and public IP networks to connect switching stations and
to interconnect with other telephony network providers; this is often referred to as
"IP backhaul".
Many telecommunications companies are eyeing the IP Multimedia Subsystem (IMS)
which will merge Internet technologies with the mobile world, using a pure VoIP
infrastructure. It will enable them to upgrade their existing systems while embracing
Internet technologies such as the Web, email, instant messaging, presence, and
video conferencing. It will also allow existing VoIP systems to interface with
conventional PSTN and mobile phone networks.
All contents copyright (c) 2009 ZyXEL Communications Corporation.