[ale] Rant
Scott Plante
splante at insightsys.com
Wed Jul 13 20:22:25 EDT 2022
It refers to HD Voice. Way back in the early days of telephone switching,
they developed a very basic audio compression known as alaw or ulaw. It's
not bad for the narrow range of frequencies used by spoken voices, but
nothing like what we are used to today for non-telephone audio. For a long
time PBXs and phones didn't worry about better quality because it was going
to go through one or more phone companies that would downgrade the
compression to ulaw anyway (alaw was almost the same, but used in Europe).
With the advent of VoIP we began to have a decent likelihood of a call
never going over old POTS (plain old telephone service) anywhere in between
and IP desk phones started offering what became known as "HD Voice". It has
a wider frequency range and takes advantage of much better compression
algorithms (e.g. G.722). Not too many years later, cell phone manufacturers
and service providers began offering it too. It remains true that it's only
useful if your whole call bypasses POTS--it could be cellphone to
cellphone, or VoIP to VoIP, or other configurations but both ends and
everything along the way have to support it. It's still not going to be the
quality of your high-end music setup, but it's much better than traditional
telephone service. Of course you're still at the mercy of the microphone
and speaker on both ends too, like you are listening to a high quality
recording on crappy earbuds, for example. This is all from memory, but
we've been using HD Voice with Asterisk PBXs and Polycom phones for many
years now. If you Google "HD Voice" you'll find a lot of resources.
On Thu, Jun 30, 2022 at 11:27 AM Boris Borisov via Ale <ale at ale.org> wrote:
> On my Verizon phone when I make phone call there is little HD sign next to
> keypad.
>
> Do they want me to believe that I'm listening to the other voice in Hi-Fi.
>
>
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