Re: TI-H: TI-Modem a reality

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: TI-Modem a reality
From: tsaimelv@pilot.msu.edu (Mel Tsai)
Date: Thu, 07 Aug 1997 00:58:10 GMT
In-Reply-To: <33E915AA.AD6A67F@capitol-college.edu>
References: <33E8B97E.6A9460B2@hotmail.com> <33E915AA.AD6A67F@capitol-college.edu>
Reply-To: ti-hardware@lists.ticalc.org

>Standard phone-lines are 12V, and when it rings, it's 90V.  I believe
>that the link port on the ti calcs uses 5V/0V for it's signals.  So to
>hook-up the 92 directly to a phone-line would require voltage regulators
>and/or resistors.  As for the protocols, I'm not sure how hard that
>would be to program, but i'd imagine that it would just be easier to
>find an old 9600 baud modem.


Well, phone line signals are *analog*, whereas the TI linkport is TTL
(digital).  That means that analog/digital and digital/analog
conversion would be necessary, and it would have to be FAST to keep up
with the phone.  Basically it's almost impossible without some pretty
complicated modulation circuitry, all of which is present in your
standard modem.

-Mel

References:

TI-H: TI-Modem a reality

From: Joe Martis <bungix@hotmail.com>

Re: TI-H: TI-Modem a reality

From: Rigor Mortis <ksmith@capitol-college.edu>