Serial Printer Version

[RWAP]

We were asked recently to help replace some receipt printers in point of sale self-service kiosks.

As the printers would no longer be used - there was no processing of the data required other than to simply spool it to an empty device - or so we thought.

This was quite a learning curve, as we realised that although the printers connected via USB, the USB port actually worked as a virtual COM device; so this meant that our existing approach did not work.

Not only could we not obtain all of the USB parameters needed using our usual method for a standard USB printer, but we found that there were several commands which needed to be emulated in order to report on the status of the printer.

Several days working out how to replicate a virtual COM device on an Odroid C4, we managed to get Windows based PCs to actually recognise the device as a printer and allow us to send a test page to it.

Unfortunately, the Kiosk is still refusing to recognise that there is a printer attached and just goes into error!

It has been a steep learning curve so far, but we will not let it beat us.