Tapping data into a USB printer

Question

I don't know how to ask the question so I will describe what was done previously with serial and I'd like to know if it can be duplicated with USB.

In the old days, POS systems spit out ASCII data through a serial port, usually RS232, to send the data to the printer. This could be "sniffed" using a Y splitter and running a parallel "sniffed" line to a digital video recorder.

Now that the POS systems use USB to send data to its printer, I would like to know if the USB can be split like the serial in the old days, add a USB to serial converter and then run the serial cable to the DVR to receive the same data packet (ASCII?) to a digital video recorder.

Any help in this matter is appreciated!

Tony

Answer 1

It really depends on the type of printer. Some POS printers (especially thermal ones) still run over serial, they just come with a built in usb to serial converter on the PCB, as serial ports are rare these days.

If you take it apart and take a look at the chip that the USB traces connect to, you might be able to see if it's a usb to serial converter. At that point you may have to look up the data sheet for the chip and figure out what the TX and RX lines are, and then hook a scope up to them.

But, like I say, some printers aren't even using serial for transmission these days, so this may not be the case.

Answer 2

You could try to sniff the USB port traffic using software like wireshark or USBPcap and then send the file/stream from PC to the DVR.