Retro Computer / Equipment > Centronics Port > Retro-Printer Module > USB > Printer

The Retro-Printer Module is a small module ("HAT") designed by Retro Computer specialist, RWAP Software.

The module plugs into a Raspberry Pi (or other Single Board Computer) to allow you to connect a centronics port on older (vintage) computers and equipment to any modern printer such as a USB or network printer; converting the output as necessary.

Easily connect anything from a DOS program; a 1980s Home computer; an industrial lathe; test equipment; door entry system; or even PLC controlled equipment to a modern, low-cost printer. You can also use the module to capture printer output sent to a parallel port and store it for future reference or manipulation.

This makes the module ideal for both producing hard copies of printed output on modern printers, or for capturing data from old equipment; removing the need for legacy printers and enabling migration of data to modern systems and software.

Capture Parallel Port Data > Capture Data to File > Convert to PDF > Print to Modern Printer

What is the Retro-Printer Module?

The Retro-Printer Module (HAT) designed for the Raspberry Pi

Designed as a plug in module (HAT) for the Raspberry Pi computer; the Retro-Printer Module connects the latest USB and network printers to a centronics port.

Developed by retro computer specialist RWAP Software, the Retro-Printer is a hardware and software printer emulator that connects to a parallel port and interprets input in either ESC/P2 or PCL format.

It understands both text and graphics (including the ESC.2 and ESC.3 compression modes) and converts this so that the output can be stored electronically or sent to a modern USB or Network printer.

Specifically designed to provide a solution for computers and equipment which would otherwise send output to a dot matrix printer, the module is ideally suited for providing a modern printing solution for a retro computer; as well a wide range of industrial and medical equipment.

Why is the Retro-Printer required?

Many retro computers were designed at a time when dot-matrix, daisywheel and impact printers were prevalent. A lot of industrial equipment (and DOS based application software) was designed to use these printers, incorporating the same printing methods.

Applications ranged from word-processors and desk-top publishing solutions to simple reports and data-logging. Text and graphics could easily be mixed on a page and printed without needing a complex printer driver written which was dependent upon the make and model of the printer.

Dot matrix printers commonly used the ESC/P (and ESC/P2) printer control language made popular by Epson. Printing was as simple as connecting a printer to a parallel port and sending a string of plain text to the port. The printer control language then told the printer if you wished to output text in bold, italics or a different font.

As a result there are 1,000s of DOS based programs and industrial equipment which expect a connected printer to understand and print simple text and graphics.

When Microsoft Windows took the market by storm in the 1990s, printer manufacturers seized on the opportunity to make printers “dumb” and most printers available to purchase today are GDI Printers.

A GDI printer or Winprinter is a printer designed to accept output from a host computer running the Graphic Design Interface (GDI) under Windows, Mac OS-X or Linux. The host computer is responsible for all print processing and then uses the GDI software to send a bitmap of the printed page to the printer using a printer driver normally supplied by the printer manufacturer.

Whilst early printers require hardware, firmware, and memory for page rendering; a GDI printer is cheaper to produce (and thus to purchase). Unfortunately, this means that a GDI printer cannot be used easily with non-standard operating systems, or even a lot of DOS programs. These printers cannot even understand a simple line of ASCII text characters sent to them such as the standard test “HELLO WORLD”.

Solutions which enable you to replace a centronics printer with a modern USB or network printer are few and far between:

• A handful of software based solutions exist which run under Windows and re-direct the centronics port and then utilise Windows printer drivers to output to any connected printer.
• The Retro-Printer represents one of just four hardware solutions that we have come across during our research over the past few years (at least one of which no longer appears to be available).
  
  A hardware solution has the benefit that it can physically replace a centronics printer, by connecting directly to a centronics / parallel port. However, the Retro-Printer does this at a fraction of the cost of the other solutions.

What other options do users have?

• Upgrade to new software, or most probably use an alternative program, or equipment which can run on the latest operating system and use its in-built printer drivers
• Purchase an expensive dot-matrix printer or top-end laser printer which supports plain text and DOS software. These type of printers are increasingly hard to find and generally cost upwards of £200.
• Track down second hand printers which could be used as a direct replacement whilst risking the availability of replacement ink cartridges / ribbons and spare parts.
• Disable printing altogether

Why not use a virtual printer to capture the printer port?

One common solution to this, is to install a “virtual printer”. A virtual printer is a piece of software which runs on a Windows based PC and monitors the installed parallel ports on the computer itself. There are several virtual printers (or DOS Printers), available for Windows based computers.

Provided that your program runs as a DOS based application program which can run within a DOS box as part of Windows 95 or later, then these DOSPrinters can work quite well at capturing the data sent by to the parallel port (LPT1 to LPT9) and then redirecting it to a connected GDI printer using Windows to perform all of the hard work.

Unfortunately, there remains a whole host of circumstances where such a virtual dot matrix printer cannot be used. For example, consider how you would print (or collect the data) from test equipment, medical equipment, industrial machines or vintage computers which do not run Windows; but use their own operating systems (or plain DOS).

Hardware based Virtual Printer Emulation

The Retro-Printer Module is designed to perform a similar function to softweare printer emulators. However, it is a hardware solution, so rather than a simple software emulation of a traditional dot-matrix or daisywheel centronics printer, the Retro-Printer forms a low cost centronics to usb (or network) printer convertor which can be used seemlessly to print the captured text direct to any modern connected network or USB printer, such as a low cost Inkjet, or even a laser printer.

Connecting to an industry standard parallel port (you need a parallel to centronics cable), the Retro-Printer captures and converts any data intended for a printer. Although primarily designed to act as a virtual Epson printer, the Retro-Printer module can handle ESC/P, ESC/P2 and HP PCL data. We will also work with customers and industry to produce further virtual printer support where required.

You can even use the Retro-Printer as a simple centronics to USB convertor, which echos the data captured from the centronics port directly to a connected USB printer. This can be used, for example, to replace a centronics HP PCL printer with a modern USB model.

Create Electronic Documentation

Many of us will remember the promise of a “paperless office” back in the 1990s – this has unfortunately, never truly come to fruition, although there comes increasing pressure to store documentation electronically, rather than on paper.

Unfortunately, there is a wide range of equipment out there (such as data analysers, opthalmic equipment, test equipment and injection moulding machines) which has to produce a physical print out which can then be scanned and stored for future use electronically. What a waste of paper and time!

This is where the Retro-Printer module comes to the fore. You can connect it in place of a physical printer and then use the built-in virtual printer convertors to take the captured data and convert it to PDF or even extract it as plain text files, stored on a USB memory stick or made accessible over a network, without the need to produce a physical print out.

If you do insist on a physical print out also (say for auditing purposes), then the Retro-Printer can be configured to also create that alongside the electronic version.

The possibilities are countless!

Supported Applications

The Retro-Printer Module connected to the Raspberry Pi – ready for a computer to connect to the Retro-Printer’s centronics connector

The Retro-Printer Module has been designed primarily to replace an Epson standard ESC/P printer (such as a dot matrix printer, or early Epson inkjet printer), or a Postscript printer (HP PCL).

The Retro-Printer can understand plain text, or text formatted using Epson ESC/P and ESC/P2 control codes, together with graphics sent to it in Epson ESC/P or ESC/P2 format (including TIFF and Delta Row Compression modes – 180dpi to 1440dpi).

Whilst we do not provide our own HP PCL interpreter, this data can be captured and, by installing GhostPCL on your Raspberry Pi; you will be able to convert the captured data to PDF or output it to a modern USB printer.

For the majority of applications which expect to send their output via a parallel port to a HP or Epson printer, this will allow you to connect a modern low cost printer in its place. You may wish to verify if your application (or software program) outputs either plain text, or allows you to select an Epson or HP PCL printer driver (such as Epson FX-80).

Applications may range from a DOS based program, a retro computer, such as the Sinclair QL, Sinclair ZX Spectrum, Amstrad PCW and Commdore Amiga home computers, or even the parallel (centronics) port attached to an industrial lathe; which outputs simple log files and status codes; or even replacing a dot matrix printer connected to a PLC.

Commodore C64 Example Ouput

Basically, if you have a piece of test equipment, legacy computer or anything else which has a standard parallel port then the Retro-Printer can capture the data and allow you to store it electronically, or print on a modern USB printer. Even if you have a non-standard centronics port, then we can work with you to decode the output and provide you with a means of collecting and converting the data.

Successful Implementations

To date, we are aware of users who have successfully used the Retro-Printer with the following:

• Acorn BBC Micro (B) Home Computer
• Audio Precision ATS-1 (high-end audio measurement system)

• Audio Precision AT-1 Example Ouput

  Commodore Amiga A1200 Home Computer
• Commodore C64 Home Computer with a W&T92000 serial to centronics adaptor
• Door Entry Systems
• Escon R50 Brake Testing Machine
• FSA Spectrum analyser by Rohde & Schwarz
• Oric / Atmos Home Computer
• Siemens CP-523 Serial module on a Siemens S5 PLC
• Sinclair QL Home Computer with a Miracle Systems Centronics convertor
• Strobe Data Products HAWK System (Data General Nova and Eclipse replacement)
• Teltek C60 Checkweigher
• Zeiss Humphrey Automated Peripheral Visual Field Analyzer

Connecting to a Serial Port

TelTek C60 Example Output

If you have a serial port rather than a parallel port, you may need to obtain a simple centronics convertor – there are plenty of these available on the second hand market (if there is sufficient demand, then we may produce a serial version of the Retro-Printer).

In the meantime, we have developed an experimental version of the software which captures serial port data sent to a serial to USB adaptor connected to one of the Raspberry Pi USB ports. If you wish to explore this possibility, please contact us for further details.

If there is sufficient call we will look into adding support for other output printer formats, such as ESC/POS format.

We are also open to new ideas and calls to add additional functionality.

What You Need

1. A Single Board Computer - ideally a Raspberry Pi quad core version (Raspberry Pi 2, Raspberry Pi 3 and Raspberry Pi 3 Model B), as these will fit in the case we have designed and offer separately.  You will also need a suitable power supply for the Raspberry Pi.
   
   
2. A centronics cable - the Retro-Printer connects via an industry standard centronics connector.