[TriLUG] VoIP SIP MODEM?

[Alan Porter]

> What you are talking about is simply a codec.

It's funny, the cellular companies do the same thing.  At least, the GSM
providers (Cingular, AT&T Wireless) do for "circuit switched data" calls.

You buy an all-digital phone, and you hook it to your PC to surf the net.
You would think that you've got an end-to-end digital connection.

However, your ISP doesn't know anything about cell phones... they are
expecting you to dial up using an analog modem.  So the cellular company
routes data calls through a bank of out-dial modems!

cell phone --- tower --- switch --- modem pool ~~~ ISP modem --- internet

In Europe, the GSM providers offer a chioce between analog modems or
ISDN, so it's possible to go all-digital.  Here in the US, many carriers
(Sprint, Verizon, Alltell) are using the CDMA standard.  Rather than allowing
you to call an existing ISP's modem, they simply act as the internet service
provider themselves.  You get the all-digital connection, but then you're
forced to use the carrier's internet service.

Alan Porter
(former Ericsson employee)