Re: NULL modem projects

[jruschme@hiway1.exit109.com (John Ruschmeyer)]

In article <1342551240-970307124700@rook.wa.com>,
Brian Hammack <brian.hammack@rook.wa.com> wrote:
>
> JE| 2) Is it possible to make a *serial port* out of a <Insert name of
>   | old    300/1200/2400 baud modem> modem?
>
>Trying to figure why the RS232 of the serial card isn't good enough...

Maybe I should clarify. My assumption from all the "null modem" posts is
that there are a lot of people whose Apples have internal modems as
opposed to serial cards. Further, many of these are of the 300/1200 baud
variety.

In my limited experience, it seemed that such a modem consisted of some
bus logic, a UART, and some modem circuitry. I was positing the question
of whether anyone had taken an obsolete internal modem and converted it
into a serial port. The advantage being that one *should* be able to get
a higher transfer rate than is possible through the modem hardware.

There is some precedent for this. In the CoCo (Radio Shack Color Computer)
world, it is a popular hack to take the old RS 300 Baud modem pack, cut
off the half of the board with the modem circuit (leaving behind the 6551),
jumpering two cut traces, and tacking on a small circuit containing a
DB-25 and some line drivers (1488/1489, etc.).

Any thoughts?

<<<john>>>