Adapter to connect the DB9 serial port of computers or microcontroller systems to the USB port of printers.

This 1.8m adapter cable has a female 9-pin Sub-D connector to connect to the serial port of computers on one end and a USB-B connector to connect to the USB port of printers on the other end. It requires no drivers or software (in most cases), and converts the RS232 printing protocols to USB.

This adapter allows you to replace your old printer without having to replace your established system. Use it to connect modern printers and multifunction printers that have a USB connection to the DB9 serial interface of legacy PCs, measuring devices, laboratory and diagnostic devices, control panels, medical devices as well as all other products that were designed with a serial port interface. Note however that only printing is supported; scanners, PC-Fax and Software Toolboxes are not supported.

GDI printers (without their own emulation) are not supported. (Look at the specs of a printer on the manufacturer's web site and see if there is a section about emulation, PostScript or HP PCL. If there isn't one, then it is a GDI printer. You also can recognize a GDI printer by the fact that it won't have Linux listed as a supported operating system.)

The adapter cable comes with its own 100-240V, 50/60Hz power supply with interchangeable U.S., UK and European power plugs.

Serial-to-USB Adapter Features

Connectors

• 1x DB9-F
• 1x USB-B

Power Supply

• Input: 110-240V @ 50/60Hz
• Output: 5V / ~100 mA
• Cable: ~1.8m

USB Interface

• USB1.0 Low-Speed (1.5 MBit/sec)
• USB1.1 Low/Full-Speed (12 MBit/sec)
• USB2.0 Low/Full-Speed
• Class: Printer / Hub

Serial Interface

• Speed: 2400 to 115200 baud
• Protocol: None, RTS/CTS, XON/XOFF
• Parity: None, Odd, Even
• Data bits: 7, 8
• Stop bits: 1, 2

The SER2USB comes programmed in an automatic configuration mode. Just send it an initial print job of at least 1000 characters and it should determine the correct serial settings and configure itself accordingly, printing a status page. If the automatic configuration should fail or you ever need to change the serial settings, you can use a terminal program like HyperTerminal or the XT-ADMIN-XXL Tool. This tool and the instructions are included on the CD-ROM shipped with SER2USB also.

Usage with a Microcontroller System

Print formatting like bold, larger text, etc. is done typically via printer drivers. Those normally are part of an operating system such as Linux that runs on 32-bit microcontrollers.

For a microcontroller that does not run its own O/S with printer drivers, you can take the following approaches to print:

• 1. The easiest way to send something to the printer is simply to transmit ASCII characters. This gives you limited formatting capability. You can, for example, control line break by sending an ASCII new line and carriage return character. You can eject a page by sending an ASCII form-feed character (0xC in hexadecimal).


• 2. If you need more formatting control, you must implement a printer language (or the needed subset thereof) such as HP PCL5 or PostScript in your microcontroller code (for this to work, you will then of course need a printer that supports HP PCL5 or PostScript). This sounds complicated, but is in fact relatively easy, as each formatting control code is just a string of specific ASCII characters.

In HP's Reference Manual for PCL5, you can find the definition of the PCL5 printer protocol and the control codes used to do formatting.

For more info on PCL codes, see also this third-party PCL Escape Sequence Reference Page.

This then would work as follows, for example:

[control code for printer to enter PCL mode]
[control code for bold printing on]
Text that you want to print in bold
[control code for bold printing off]
More text
[more controls]

Please note that you will need a USB printer that has its own built-in emulation (PostScript, HP's PCL, or a variant thereof). Many cheap USB printers on the market are what is called GDI (Windows Graphics Display Interface) printers, i.e. they depend on the Windows Graphics Display Interface component to do the rendering of the characters. These GDI printers will not work with the SER2USB adapter.

Look at the specs of a printer on the manufacturer's web site and see if it has a section about emulation, PostScript or HP PCL. If it does not, then it is a GDI printer. You also can recognize a GDI printer by the fact that it won't have Linux listed as a supported O/S.