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VoIP Voice and Fax Signal Processing by Sivannarayana Nagireddi

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9.1 WIDEBAND VOICE EXAMPLES

In this section, some popular and feasible wideband voice call operations are presented.

9.1.1 Wideband VoIP Calls with Computer Softphones

In the actual use of VoIP, wideband voice started gaining popularity for the last few years (while writing this chapter in 2007). Some personal computers (PCs) and laptops were using software applications like Skype that was using iSAC [URL (iSAC)] as a wideband codec for end-to-end VoIP calls. PCs and laptops had full audio-capable support on the interfaces. Headsets used with analog interface are wideband capable. This makes a reasonable good example of an end-to-end simple wideband VoIP call. Skype also supports other codecs and some VoIP calls may not use wideband codecs.

9.1.2 Wideband IP Phones

Some IP phones support wideband voice mainly with G.722 and G.729.1 compression. The main requirements for wideband voice support are in the extra processing required, four-wire analog-to-digital converter (ADC)/digital-to-analog converter (DAC) hardware interfaces and acoustics capability in handset and speakerphone-mode acoustic requirements. Once acoustics are taken care of, processing and hardware interfaces may not play a major role in the wideband IP phone.

9.1.3 WiFi Handsets

WiFi phones also known as the wireless fidelity (WiFi) handset interfaces through the family of 802.11 wireless local area networks (LANs) protocols. These are self-contained VoIP phones. WiFi phones can make independent VoIP calls through ...

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