A short while back I addressed the question of how DECT & CAT-iq may foster the broad deployment of HDVoice. At that time I described one possible scenario where carriers would deploy customer premises equipment (CPE) with an on-board cordless base station. Although a frontrunner, and the basis of Comcast’s (decidedly non-HD) HomePoint service, this is not the only approach afoot. There’s another possibility arising that involves conveying HDVoice over a plain old analog RJ-11 connection.
At first glance HDVoice and analog lines would certainly seem to be mutually exclusive. The common wisdom is that wideband telephony requires the use of an all-IP call path. This is in fact a generalization, and not absolutely true.
Firstly, it has long been possible to pass wideband audio, in the form of G.722 encoded media, over the PSTN by way of ISDN connections. Also known as BRI interfaces, an ISDN connection supports up to two 64 kbps channels (bearer channels) and one D channel for the purposes of call setup & teardown signaling. High-quality voice using G.722 was one of the selling points of ISDN in the 1980s.