ZyXEL Communications 2602H Series User Manual

Prestige 2602H/HW Series User’s Guide

138

Chapter 8 Introduction to VoIP

A codec (coder/decoder) codes analog voice signals into digital signals and decodes the digital 
signals back into voice signals. The Prestige supports the following codecs.

G.711 is a Pulse Code Modulation (PCM) waveform codec. G.711 provides very good sound 
quality but requires 64kbps of bandwidth.

G.729 is an Analysis-by-Synthesis (AbS) hybrid waveform codec that uses a filter based on 
information about how the human vocal tract produces sounds. G.729 provides good sound 
quality and reduces the required bandwidth to 8kbps.

Dual-Tone MultiFrequency (DTMF) signaling uses pairs of frequencies (one lower frequency 
and one higher frequency) to set up calls. It is also known as Touch Tone®. Each of the keys 
on a DTMF telephone corresponds to a different pair of frequencies.

Pulse dialing sends a series of clicks to the local phone office in order to dial numbers.

1

Enable Message Waiting Indication (MWI) enables your phone to give you a message–
waiting (beeping) dial tone when you have a voice message(s). Your voice service provider 
must have a messaging system that sends message waiting status SIP packets as defined in 
RFC 3842.

1.

The Prestige does not support pulse dialing at the time of writing.