Re: Parallel Printer on IIc

[et472@FreeNet.Carleton.CA (Michael Black)]

zeem (alex_taylor@REMOVETHISntlworld.com) writes:
> Jason Harmon wrote:
>> Hi,
>> 
>> Given the the IIc has only a serial port for printers, can anyone tell me 
>> what type of serial to parallel adapter would allow me to connect a generic 
>> parallel printer (such as an Epson)?
>> 
>> Does any generic serial to parallel adapter work for this purpose without 
>> special software?
> 
> I don't know if these are easily available any more, but simple adapters 
> like this do exist. I've got one for my Sinclair QL computer (which only 
> has serial ports), as far as the computer's concerned it's just like 
> connecting a serial printer.
> 
I was going to post, and then realize I don't have a clue whether they
are still being manufactured.

But yes, my take is that they would have been generic.  I imagine many
were just a UART and peripheral ICs, no CPU, and that wouldn't allow
for anything but the conversion from serial to parallel.  Or looked
at a different way, there was more need for the serial to parallel
conversion than for one that did serial to parallel conversion and
some sort of data conversion.

The special software was often because of the computer.  The Macintosh
seems to be the most obvious example.  It was intended for use with
the Imagewriter, which was designed for the Mac.  The control codes were
not standard.  The only way to add a non-Imagewriter was to get a driver
that took the stuff intended for the Imagewriter and translate that into
the codes needed by the third-party printer.  Printers that took serial
input were far less common than parallel printers, so to use a non-Imagewriter
with the Mac, you tended to need the hardware.  But you needed the software
because the parallel printer wasn't control-code compatible with the
Imagewriter.

Serial to parallel converters were relatively common twenty years ago,
because there were a number of computers that only had a built in serial
port, but all those parallel printers.  I made a serial to parallel converter
for my Radio Shack Color Computer (that only had a serial port), and it
was just a UART, a clock, and some "glue" ICs to hold it together.  It
worked fine.

WHen I moved to a Mac Plus I ended up with a copy of Word that had built
in drivers for various printers, including a generic Teletype machine.
My serial to parallel converter didn't work, there wasn't enough handshaking
for the faster Mac Plus and I lost bits, so until I got an Imagewriter
at a garage sale, I fed the Mac Plus into the serial port of my Radio
Shack Model 100 laptop, which echo'd to the parallel port, and I got
my serial to parallel conversion.  Of course, I had to run Word every
time I needed to print something.

ANd that would actually work.  Find some other computer with a both
a serial port and a parallel output port, hook the printer to the
parallel port, and the IIC to the serial port, and then run a terminal
program on the second computer.  In the old days, those would often
have the ability to copy everything going to the screen to the printer,
and that would give the needed serial to parallel conversion.

A bulky workaround, but it's pretty easy to find an old computer
for nothing, and right nearby.

  Michael