31 Jan
2025
31 Jan
'25
8:19 a.m.
On 31/01/2025 15:23, ben via cctalk wrote:
On 2025-01-31 7:06 a.m., Frank Leonhardt via cctalk
wrote:
I wanted to get a REAL computer for a long time, since the 70's and
now I have
nice 18 bit home-brew design, using 2 1508 CPLD's and 6 74LS219's for
the ALU and a 1508 for the control logic.
Back then you could get TTY's and other HARD copy output devices
and paper tape I/O.
Now that have my 1977 computer (It uses 68A50 ACIA's) is there low
cost paper tape punch/reader emulator for just a plain 1200 baud
serial port? All I have working now is just a serial boot strap and
some ram.
I've still got a few actual teletypes. Be careful what you wish for. I
was going to suggest searching eBay for an ASR33 but I checked and there
aren't any.
My 1970's computer had a switch on the one ACIA between a Teletype and a
a CUTS cassette interface. The latter stored at 30cps. An advantage to
the CUTS is that you can't get paper tape easily AFAK (This list is
probably the place to ask).
I'm not sure how an emulator would look TBH. It wouldn't have the charm
of the original, but I do see your point. What were you thinking? Hard
copy or VDU? I see you can still buy matrix printers which, with the
appropriate driver, could be persuaded to do one character a time. I see
on Amazon they now cost a lot more than laser printers!
And store "paper tape" as files on a USB stick? Or you could use a
cassette, although they're getting hard to find. The FSK circuitry is
pretty straightforward (copy it from an OSI 600 board
https://osiweb.org/manuals/600revB.pdf Sheet 7).
And I don't know where you'd find such an awful keyboard - although you
could make one yourself out of 53 key switches. The final touch would be
a powerful subwoofer to make the whole house shake when you pressed a key.
I'd be up for working on one.
If you wanted a purely software emulation then any glass TTY program
that was able to record and play back from disk would do the job.
I also checked and you can still get electric typewriters. Brother does
one with a daisywheel; Silver Reed has a much cheaper dot matrix. I
don't know, but I suspect some of them still have computer interfaces.
So when did serial printers show up?
For home computers, from memory....
The big one was the Epson FX-80. They tended to have parallel interfaces
- cheaper than serial! You could buy a serial board to fit in to them
(I've got one knocking around).
A Teletype is, of course, a serial printer. And it was all I could
afford. £50 at the time, whereas a matrix printer was £200.
A few years later people were chucking out teletypes, so I picked up a
few more for spares.
Regards, Frank.