Bluetooth printer

Some time ago I got my hands on a couple bluetooth-enabled thermal printers. These also had RS-232 input, and were relatively cheap so I was a bit excited; I've been looking for this kind of printers for some time for my purposes.

Very quickly my excitement died, though. Although printer could be connected with RS232 and bluetooth at same time, these interfaces couldn't be used when both were connected. So effectively, this printer is useless to me.

I contacted the manufacturer for help, and their response was essentially that this is by design and there is nothing they can do. If RS232 connector is connected, bluetooth printing is disabled to prevent situation where printing were requested from both sources at same time.

While I understand the reasoning - after all, I wouldn't like the situation either where I had data from both sources mixed on same paper - I was mostly dismayed because they essentially refused to acknowledge that this is actually an very easily solvable problem.

You only need two print buffers. Data received from RS232 goes to one, and data from bluetooth to another. When printer is idle, printing from one buffer is committed, and other stays there, gathering data, until first receipt is done, and then buffers are switched - possibly after short idle timeout. Simple, effective and exactly what I'd need - there printers after all are used only occasionally to print single receipt and then it sits idle for a period.

But no, whatever the reason is, they just couldn't or wouldn't do it. So guess I'll need to keep looking for better units.