🚀 go-pugleaf

gilchr@ee.ualberta.ca (Andrew Gilchrist) writes:
>While I don't argue that such a sampling/compression/encryption/
>transmission/decryption/decompression/reconstruction could be done virtually
>in real time on a typical phone line with a lot of funding, I will need
>some math and some specifications for devices capable of carrying this out
>reliably on an analog cellular network before I am convinced.

As I've said, you can buy the equipment from AT&T today. Really. No
joke. No need for you to contemplate "a lot of funding" -- you can
just go out and buy the equipment any time you like. AT&T is the only
vendor I know of that packages this all with a cellular transmitter,
but you can buy similar phones from Cylink, Motorola and other
vendors. And this is just the list of DOMESTIC manufacturers of such
things -- doubtless there are folks outside the country that make
them, too.

Its all really easy. CELP compression can be done with cheap DSPs --
you can buy the code if you don't feel like writing it yourself. The
encryption can be done an order of magnitude faster than you need even
on conventional processors.  V.32bis modem modules are a dime a dozen.
You don't need to be AT&T to do this -- any talented EE with a few
weeks of work could put a system to do this together.

>I don't have
>bandwidth specs or s/n values for cellular transmissions, so I can't do this
>for myself.

Analog cellular phones handle the standard 300-3000Hz phone band
perfectly well. V.32bis modems operate just fine on them.

Perry
--
Perry Metzger		pmetzger@shearson.com
--
"They can have my RSA key when they pry it from my cold dead fingers."
Libertarian Party info: Phone 1-800-682-1776, E-Mail 345-5647@mcimail.com