I am not entirely sure if this is the right place to ask, but I figured if someone knows y'all here would.

I have an HP54645D oscilloscope, and it can print the screen on a printer that's connected via parallel port. With the scope I got a HP LaserJet 6P, and I would like to replace said printer with a newer model.

However, as you may have guessed, that presents the problem of communication with the printer. The scope has a few presets for printers:

  • LaserJet
  • Plotter
  • DJ Mono
  • ThinkJet
  • Epson

Does anyone here know what that actually affects in terms of communication? Do modern printers work with any of those settings?

Update: I have found a replacement cartridge for the LaserJet 6P, so no worries, the printer stays until I can't find a cartridge, and now that I know it uses PCL, I can also easily set it up on my computer.

  • Well, surprisingly there are printers (and still in production as far as I can tell!!!) that have a parallel port. Commented Feb 12, 2022 at 20:56
  • Well, I'm not sure if those adapters work in reverse, and the old printer needs a new toner cartridge, and the cheapest I could find is around 80 bucks for it. For that price, I can buy a modern printer with a parallel port. Commented Feb 12, 2022 at 21:06
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    @VincentGuttmann Then again, why throwing away a working printer? Be assured that a HP LJ 6P may be way more reliable than any printer available at 80 Euro - no need to produce even electronic waste. As tomas points out, HP LJ cartridges go quite a distance and USB to parallel is cheap. Also, the 6P is maybe not top of the line anymore, but for sure one of the most widely supported printer ever. Also, you may take a peek on ebay for LAN interfaces (600N IIRC). Would speed up the spooling but as well allow connecting to your PC (via LAN) and the 'scope without unplugging all the time.
    – Raffzahn
    Commented Feb 12, 2022 at 22:51
  • 4
    @Raffzahn - Indeed, those 6P printers were bullet-proof workhorses. I would much rather spend 100 Euro on a new cartridge than worrying about compatibility (and costs for new cartridges for the new computer).
    – Jon Custer
    Commented Feb 14, 2022 at 17:42
  • 1
    Update: I found a cartridge for 50€ so the printer stays until I can't find a cartridge any more. Commented Feb 15, 2022 at 7:04

3 Answers 3


[Asking for what to buy is even less valid here than asking for new tech - this is both, so let's assume you're asking about the underlying (historic) standards :))]

It's safe to assume that the 'LaserJet' entry stands for use of PCL5. It's a set of escape sequences for printer control introduced by HP. So what you're looking for is any printer that offers PCL5 compatibility. PCL6 might work as well and PCL6 printers are usually PCL5 compatible, but looking specifically for PCL5 will be on the safe side).

The 'Epson' entry probably covers any printer accepting ESC/P commands. A similar, but older (and incompatible) standard introduced by Epson for their printers.

ESC/P has its roots in line printers, while PCL is specifically made for page printers.

As Tomas By points out, selecting the 'Plotter' entry may most likely end up sending HPGL commands. HPGL was introduced by HP in 1977 specifically for their HP-8972 plotter, but quickly became a de facto standard for plotters. HPGL is still supported by many modern devices, usually upper end (ink) plotters.

Essentially, these three languages are the bedrock of printer control before postscript (or GDI) took over. They are all quite relevant for new devices as well - not least to enable replacement, much like you're asking for.

When selecting your new printer, look out for support of either standard. It might be good to check not just advertisements but data sheets and eventually manuals. Not only for supported standard, but also check if a printer can either be hard configured to one of these standards or is able to automatically select it after power up.

P.S.: Great scope BTW - perfect for retro tech.

  • 2
    Yes, that's it! The manual lists the printer as compatible with PCL 5 and PCL 6. And of course I would love to keep the printer, but its toner cartridge has run out, and for the 80 bucks that it costs, I can buy a modern printer that is a bit smaller and also has more modern connectivity. As I'm moving to a smaller flat soon, having two printers is something I do want to avoid. If I end up buying a new printer, I will try to find a new home for the old one though. Commented Feb 12, 2022 at 21:07
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    @VincentGuttmann Also remember that the toner/ink cartridges that are included with new printers are much smaller than replacement cartridges. You will soon be buying more even if you get a new printer. Commented Feb 13, 2022 at 0:05
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    I'd keep the 6P above any piece of crap you'll get for $80 to be honest.
    – Alan B
    Commented Feb 13, 2022 at 9:46
  • 3
    $80 for a cartridge? You should be able to get a compatible cartridge for an old laserjet for less than half that. As your profile says you're in Germany, I checked eBay.de and a new compatible cartridge should cost less than 30 Euros including delivery. Or you can look at DIY refilling for a design that old. I've got a much newer and flimsier HP laser and would prefer the 6P
    – Chris H
    Commented Feb 14, 2022 at 13:05
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    @ChrisH Yep, I found one for 50€ after some digging, and I decided to pull the trigger. Printer stays until I can't find cartridges any more. Commented Feb 15, 2022 at 7:02

Does the scope /only/ support a directly-connected parallel printer, or does it have other interface options?

The reason I ask is that I wrote an HP2671 emulator for my own use that connected via HPIP (aka GPIB etc.) which has the considerable advantage that it captures to a graphics file which can be immediately incorporated into working notes.

Perhaps the most interesting thing is that monitoring the commands that the instruments were actually sending indicated that they were limited to perhaps a half-dozen in total, so even if it was documented as requiring something like PCL5 going for a full implementation was vast overkill.

In fact, going for any sort of HP printer is vast overkill when one takes into account their predatory pricing policy.

  • 2
    This has been flagged as NAA, and it doesn't read like an answer (by the standards of How to Answer), but… I'm not certain enough about what the question's asking to make a judgement.
    – wizzwizz4
    Commented Feb 13, 2022 at 15:00
  • The interface card I'm using is a HP54659B, and it does support printing to parallel port, as well as RS-232, in which case it just seems to send the printer commands via RS-232. Commented Feb 13, 2022 at 15:50
  • @VincentGuttmann Using a null modem cable on the RS232 port might be a perfect way to capture the data. You should be able to use a USB/RS232 converter in case you have no old device with RS232 at hand Commented Feb 13, 2022 at 18:09
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    @MichaelKarcher Apropos intercepting output, remember that even stuff that looks like text might actually be sent as a bitmap. I had that with a Tektronix logic analyser 30 years ago: even if it was outputting a disassembly it formatted it as an Epson bitmap (I ended up writing a simple OCR program). Commented Feb 13, 2022 at 20:29
  • I reckon this is a an answer, albeit a bit of a frame challenge answer, but leading with a question it doesn't look like one and might be better starting "if you have other interfaces..." . Upvoted as an interesting and constructive alternative
    – Chris H
    Commented Feb 15, 2022 at 8:46

It may be possible to use a bit of custom hardware to read the parallel port, and pass the data on to some more modern hardware.

A quick search found me https://www.retroprinter.com/ which looks like it can handle at least ESC/P and HP PCL.

This may also allow you to skip the actual paper and print to pdf.

  • Yep, looking at the RS-232 output (the scope can print to parallel and RS-232), it seems like PCL commands for the LaserJet setting. Also, I found a replacement cartridge so the printer stays. Commented Feb 15, 2022 at 7:06

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