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While on the topic of modems...
They are used in credit card terminals. 2400 baud. Only thing they need besides the normal stuff is a reset signal. Battery...Bluetooth console...dial-up modem. Just imagine the portable BBSing possibilities! I ordered a set for experimentation. Rich -- Rich Cini ?On 8/17/20, 12:36 PM, "Lee Hart" <[email protected] on behalf of leeahart@...> wrote: 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, www.sunrise-ev.com |
