We've just seen that for regular, traditional telephony, we only need an audio source that is mono, narrowband, 8 bit, 8 khz. That is considered good quality, toll-grade quality.
It compares well with cellular phones' quality, which in the last decade has drastically lowered our expectations. Cellular phones' codecs did not sound very good; actually they were much worse than G711 or G729. But we're on the verge of a revolution in the sound quality of telecommunication.
First it was Skype, who introduced us all to 16 khz, wideband audio. Ever tried to listen to music via Skype? It sounds good. And speech too: You immediately hear and feel, you're not on PSTN (and neither on cellphone).
But there is much more to come: 4G and LTE cellular networks are starting to become available everywhere, with audio in ultra-wideband and high definition (HD). The cellular network will once again change our expectations, but this time it will raise the bar...