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Looking for help: Capture printer data on parallel port
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james_s:
The Arduino could almost certainly capture the data, but what about the other half of the equation, communicating with a modern printer via USB or perhaps ethernet. It's going to have to be a printer that has a real controller on board, not one of those cheap ones that rely on a Windows driver to do most of the work. Of course you could capture onto an SD card or something but that creates another step.
Bicurico:

--- Quote from: nali on January 09, 2018, 06:49:13 pm ---This seems to do what you want, but they don't seem to have released it yet...

http://www.retroprinter.com/about-the-retro-printer/what-does-the-retro-printer-do/

--- End quote ---

YES! That is *exactly* what I want! Thanks! I will keep an eye on this and if the proce is right, there is no reason to try and develop something on my own.

To answer a few questions:

1) I cannot say which test equipment it is, because it is an ongoing deal, which has not been concluded, yet.
2) I don't want to actually print, I just want to capture the data and if it is just text, write my own report with it on the PC.
3) All the info I have on the test equipment is what I already posted. I don't know if the output to the printer is just text or bitmap, as well.

You have all given me some great ideas. I will now see if the device is in fact purchased.

Regards,
Vitor

SeanB:
The printers you mention are all compatible with the IBM Proprinter, or at least will print the straight ASCII that they are likely to be getting on the port, so your capture is easier, as all you will get is a few control characters on every page ( form feed, CR LF) then the data then a end of page parameter of FF, making it easy. Otherwise they might put the printer into graphics mode, which will be similar, just a lot more bitmapped data lines and then an escape sequence for the end of page.

Both are easy to decode, though the graphic printout will be poor resolution, while the ASCII will be best delivered in a monospaced font to whatever device you are displaying on so it does not have jagged lines.
Bicurico:
The device has two dip switches dedicated to select one of the 4 printe rmodels. I agree that the difference between them is probably minor and related to some control characters.

I started this thread as I was asked if the test equipment could be used to DOCUMENT measurements, without owning one of the four supported printer models.

Of course I searched eBay for a cheap listing of those printers, but there is none being sold, at least at reasonable prices.

I think I can now say that a solution is possible and it consists in hooking up some form of Arduino and send the decoded bytes from the test equipment over USB/serial port to the PC for further processing/formatting.

I thought that this application would be of general interest, as there is probably a lot of older test equipment in this situation: works fine, but only output is through some old centronics printer.

Now I need to see if the test equipment is indeed purchased and if so, I will look further into this. I keep mentioning Arduino, because I feel confortable in considering I will be able to program it as opposed to some other microcontroller. I am not a low level programmer. Also, I don't think that ther will be any timing issues, as stated before: LPT is as fast as the printer allows.

I remember that those old dot matrix printer would allow some escape sequence, where each byte would be interpreted as a vertical line of 8 pixels (or something like that). This would generate the bitmap graphics. At this point I don't know if the test equipment supports this, but I think I would be able to reconstruct the bitmap with some VB .net programming.

The linked Retro Printer looks spot on, but I just realized that there doesn't seem to be much going on... Last entry of June 2017, before 2015. Probably a dead project, unfortunately. If only they knew that there is another market besides retro computing: test equipment!  :)

Regards,
Vitor
james_s:
Given all the information, I think the arduino or other microcontroller would be a reasonable fit, either log the images to a SD card for later retrieval or send them out to the PC over RS232, either one is likely to be not too difficult.
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