exxos's Atari, Amiga & retro forum

I bought a dot matrix Atari 1025 printer the other day , it was new in box, and when I got home realized that it was 8 bit with SIO input output, but the Atari ST only has a RS232 printer input. I really like the little printer and would love to be able to use it with my Atari 520 STFM. Is there ANY way to get them to work together? I am new to the vintage computer hobby so any help would be greatly appreciated!

I'm not even sure there has been any serial printers for the ST. I'm no printer expert but I only have seen and used parallel port / centronics printers. Problem as well you would need a driver for it. Assuming the printer is standard RS232 interface it could be adapted for the ST RS232 port. But again your likely going to have to write a driver for it. Which would be hard work if you don't know the commands it uses.

If it's SIO then that isn't compatible.

The SIO port on the 400/800 is a forerunner of USB, designed by an engineer who later worked upon the USB standard.

Remember that the Jack Tramiel Atari is not the same one that made the 400/800 or that printer and the engineers who designed the ST mostly came over from Commodore with Jack.

So after reading your post I looked into it some more. The printer port is a DB25M. I was told RS232 so I just kept repeating that, never trust facebook groups lol. So I guess what I am attempting to do is go from Atari SIO to DB25M. Is that possible?

Might be easier to get an Atari 8-bit machine to work the printer :)

I would say that you should study how the SIO achieve data transfert (flow control signals, data encoding, ...) and some electrical considerations (voltages of said signal, e.g. RS-232 use ±12V signals to transmit data).

Most likely, you may have to design an adapter SIO <-> Standard interface that involve a little micro-controller of your choice (atmega, esp32, pico,...).

And maybe, someone already did this kind of work (google check -> found something : https://www.atarimax.com/sio2pc/documen ... index.html )

If you’re making a microcontroller interface you may as well make one which talks to the parallel port on the ST.

stephen_usher wrote: 17 Sep 2023 22:59 If it's SIO then that isn't compatible.

The SIO port on the 400/800 is a forerunner of USB, designed by an engineer who later worked upon the USB standard.

SIO is just regular serial port as RS232 and it is quite easy to pair them together, you have to use voltage converter: TTL (0/+5V) vs RS-232 -12V/+12V

I know people have hooked up to SIO via USB serial adapters, so I guess in theory that a serial to serial connection might be possible with the right hardware.

But, the ST uses parallel/centronics for printers and not serial, so even if you could build a suitable serial interface, you'd also need to create suitable drivers for it and that's a whole other story.

Better to get an 8 bit Atari to connect the printer to :)