Electronics Forum / Electronics / December 2004

Best hardware would be a new machine with a USB port.  Alternately an
old printer with a parallel ( Centronics ) port.

You have not a hope of getting the existing hardware to match.

Does it have a lan or wireless connection?
If so, you could use a print server.
I just purchased a Linksys/Cisco WPS54GU2, with 802.11G wireless and LAN in,
with centronics and USB2 out. Actually it's surplus to requirements now, so
if you are interested leave a message on the ng, and I will respond.

Rod

Ok, a circuit idea.

Parallel ports are TTL based, so easy to interface to any TTL interface.

Take a linux PC with two parallel ports and  USB hardware..

One parallel port has 4 available inputs, and  8 data outputs.

So 4 data lines go to one printer port and 4 data lines go to the other.

Then read the two lots of 4 bits  and then send an ack back, to get the next
byte of data..
Then translate the printer language and send it to the usb printer.

Option:
 Use a PC with one parallel port . Interface between the two machines with
a PAL.

One output from the parallel port tells the PAL which 4 bits to let through
to the inputs.

Option: switch to a 8 bit  (or 16bit) data acquisition hardware with
interrupt support.

Option: a PIC/atmel/basic stamp or other microcontroller with two lots of 8
bit interfaces, and  a PC.
Basically use the PIC/atmel/basic stamp to interface between the machines.
The data to the PC could flow by parallel port (4 bit wise) or serial port
(which at least is 8 bit).

option:  uclinux simm - has 8 bit IO, RJ45 network ... move the PC with the
usb printer off to
some other room.  should be easy to get going, hardware wise.

Thanks to all for input of this problem. Looks like there's no easy fix.
The 'machine' is a great big piece of industrial machinery and does not
have a hard drive, keyboard or Windows operating system - ie
everything is embedded.

I was hoping for a relatively simple low cost fix to satisfy the many
customers out there with this problem. However after re-examining the
problem, the solution in my mind is quite simple:

Solution....

The customers are requesting that they can use off the shelf cheap
USB printers, when the machines they have purchased range from
US$0.2M to US$0.5M apiece!!

Sometimes I wonder??? The difference in cost between a cheapy
printer and say an industrial HP parallel printer would amount to
a few hundred bucks, if that.

Even if one developed a suitable in-line interface (at great cost),
then the price of the interface + USB printer would more than likely
exceed the price of a decent industrial HP parallel port printer!

Why do customers always want something for nothing - just the nature
of the beasts I suppose!