Re: I need an Atari 400 -> 800

[bellm@mail.med.upenn.edu (Marcus G Bell)]

Dave Newton (david.newton@symbiosNOJUNK.com) wrote:
: omar wrote:
: > Also, there's a serial port on the atari, right? or a modem
: > port? or something?  (sorry, I don't know too much about the hardware
: > specs... I was probably like 6 yrs old when these machines were coming
: > out!)

:    that's cute :) I don't think they had a serial port (at least I don't
: think mine did, I had an 800, but don't remember much about it at this
: point).

Yes, the Atari 800 had a serial port, as did the 400 and the newer XL
and XE series 6502-based Ataris.

It was a 13-pin "D" connector. It ran at 19200 baud, I think, and you
could daisy chain printers, disk drives, modems, RS232 convertors, and
other stuff on it. The cassette tape storage hooked to it as well, but
didn't use the serial data lines. Rather, it used other lines specific
to the tape drive, to use the audio signals.

Since all serial devices (except the tape drive) read the serial data
coming from the computer, the serial port communicated in some
addressing scheme so that the peripherals would all know which one was
supposed to accept the command and respond to it. That meant that the
peripherals all had to be "smart" and have their own microprocessor to
decode the addresses and commands, and that meant they were not cheap.
3rd party support was minimal, but Percom made double density disk
drives with and without integral parallel (Cntronics) printer
interfaces that allowed a wider range of printer choices.

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Marcus. ( bellm@mail.med.upenn.edu )