Why "carnivore" type systems can't be (entirely) open source

[Owen Lewis]

----- Original Message -----
From: "Roland Perry" <roland@linx.net>
To: <ukcrypto@chiark.greenend.org.uk>
Sent: 12 February 2001 20:23
Subject: Re: Why "carnivore" type systems can't be (entirely) open source

>  Analogue cellphones used normal modems, albeit in the rather unusual
>  format for then - a PCMCIA card. The best data rate to choose was 4,800,
>  which actually worked better than some of the slower rates. 9600 was out
>  of the question.

I never was much of a TACS/ETACs user but I did use one in the period 89-92.
I was not aware that that any could take direct electical input from a
modem - though there would seem to be no reason why it should not have been
possible. Why the specification of PCMCIA? Was the feed to the phone not
from the line side? Acoustic couplers couplers were certainly commercially
available then and ISTR remained so through the early '90's. One used to see
them advertised for 'road warriors'.
>
> >Even now, datacom via GSM
> >is less than ideal. 9600 suks OK.
>
>  Yes, it's not that good, which is why I use a 28.8K GSM card these days
>  (Nokia Data Card with airtime from Orange).

My goodness. You have a 28.8 card or get (near to) 28.8 throughput? If the
latter I'd welcome details and so might others. How many user sub-channels
do you have to occupy?

Owen