4 Jul
2010
4 Jul
'10
9:59 p.m.
Tony Duell wrote:
Buy regular thermal paper and build
your own perforator? :-)
I keep an old
IBM Graphics Printer (Epson MX-80), HP Deskjet 500 and
an HP LJ IIIP around for printing off classic computers like my TRS-80,
Atari, Amiga and other systems.
As I've mentioned before, I consider many of the peripherals to be a part
of 'classic computing' and have no problem finding interest in restoring,
say, an HP7245A thermal printer/plotter and then using it on one of my
classic HP machines (although what I do when I run out of the special
sprocketed thermal paper is another matter...).
For the same reason I recently rebuilt an HP2631B (large, text-only
dot-matrix printer with an HPIB interface) which will get used on one of
my HP9000s (and elserhere). And of course I have a few other HPIB
printers, HPIL printers, the CX-VDO laser printer on the PERQ, and the
like.
But I probably wouldn't want to print out longlistings on any of those.
Consumables for them are getting hard to find (and expensive). Normally I
trasnfer the data to this PC and send it to my (classic) laser printer.
For machines which can be convinced to 'print' to a serial port, it's
firly easy to capture the data nad upload it (As I've mentioned before,
the HP95LX palmtop is handly for this..). For machines that have a
parallel interface (not even necessarily Cantronics), it's not hard to
make an RS232 output interface using TTL logic, a dumb UART, or a
microcotnroller (depending on your preference), that looks like a
Centroincs (or whatever) printer to the classic machine and simply
squirts the data out to the HP95...
I wonder (and it's of no use to me at the momnet)... How hard would it be
to make a device with a Centronicts-like _input_ on one side and a USB
port on the other, adn some data buffering memory. The idea is that you
link it between your BBC micro, Amiga, TRS-80, etc (which thinks it's a
printer) and a PC running suitable software. The classic machine 'prints'
to this device. the software on the PC takes the data and stores it in a
file on the PC for later formatting and printing.
My guess is the hardware is little more than a microcontroller, amybe
with a bit of logic to ensure the handshake timing is correct (a D-type
and a couple of gates). The software is another matter, though...
I've not
personally done it so please take this as semi-informed
speculation, but I think it would be not too hard based on some things
I've been reading in Nuts & Volts and Circuit Cellar. Some of the PIC
CPUs have USB capability now and there is evidently some pretty nice
support software in their library. If you didn't want to use one of
those, then FTDI has some nifty chips with a lot of the USB logic built
in. If I correctly understand what you're wanting to do then you just
need a USB client and not a USB host which makes the problem a lot
easier. If you can also arrange to have the USB client emulate a human
interface device then you avoid needing any sort of driver in the PC.
If it were me though, I think I would tend to just grab an old PC with a
parallel port and arrange a bit of logic to make that talk to the
Centronics output of the classic computer. The software (under DOS yet)
should be pretty much a piece of cake with that arrangement. Just
mostly accept input up to CR, CRLF or whatever and write the text lines
to a file. I suppose handling escape sequences might not be quite so
much fun. It sort of depends on the capabilities of the target physical
printer and just how close to the classic's printout look one was
willing to support.
Later,
Charlie C.
-tony