Richard Cini wrote:
>????????????????? Just a fun thing to do with the Z80MC and SIO card.
> With some great detective work from Josh and a little bit of tinkering,
> I was able to get the SIO connected to a Hayesmodem 300 and to get an
> old CP/M program called “MODM221A” running. MODM221A is a derivative of
> the original MODEM program from Ward Christensen.

What a cool idea! I still have my Hayes Smartmodem, and fondly remember
using it to log onto various BBS's on my CP/M computer back in the 80's.

>????????????????? Using this combination, there are a few things to note.
> First, you have to boot to the monitor and make sure that console input
> is the bit-banger only, and then load CP/M manually. There’s probably a
> way to permanently do this, but it would require modifying the system ROM.

If anyone figures it out, I can make a new ROM. There are a number of
upgrades like this that I've been meaning to get into. (Where does the
time go...)

> Second, since DTR and RTS are used as address bits, the ACE
> initialization in MODM221 has to disable DTR and RTS (or, if those are
> needed, then the RAM needs to be reduced to 32K and 5V re-routed to put
> it in the right place for the 32K RAM).

The 8250 has four output bits; DTR, RTS, OUT1, and OUT2. I supply a 128K
RAM for U1; it only needs two extra address bits. I happened to use DTR
and RTS (leaving OUT1 and OUT2 unused).

In hindsight, I could have used OUT1 and OUT2 for the extra address
bits; that would leave DTR and RTS free to use normally for serial
communications. Maybe I can do that on the next "spin" of the board.

>????????????????? I don’t have a BBS setup, but I do have all the parts
> for it – a computer with a Digi 8-port serial board and an analog
> telephone switch. So, that will be my next project.

I wish I knew more about the modern internet. It seems like it should be
possible to setup a "modern" BBS that old CP/M computers can log into.
The old modem would be replaced with a "black box" that connects to the
internet instead of a phone line.

I've seen this done; but the "black box" is a PC, complete with keyboard
and screen. In fact, you do everything on the PC itself. The CP/M
computer is redundant.

Then there is the question of what the web pages on the internet look
like that such a "BBS" accesses. They can't be the usual HTML, color,
graphics, javascript, etc. if you expect a CP/M computer to deal with
it. Examples I've seen may *look* like an old time terminal (like
<> ) but in fact it's a page full of the usual HTML,
javascript, CSS, etc.

Lee Hart

--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
???????? -- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377,