P-2302R Series User’s Guide

7.9.1 Pulse Code Modulation

Pulse Code Modulation (PCM) measures analog signal amplitudes at regular time intervals and converts them into bits.

7.9.2 G.711

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

7.9.3 G.729

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.

7.10 PSTN Call Setup Signaling

PSTNs (Public Switched Telephone Network)s use DTMF or pulse dialing to set up telephone calls.

Dual-Tone Multi-Frequency (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

7.11 MWI (Message Waiting Indication)

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 supports DTMF at the time of writing.

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Chapter 7 Introduction to VoIP