I work with cash registers that are bare-boned RedHat Linux boxes. These registers have a scanner attached to a serial port (ttyS2).

We do a lot of testing that requires someone to stand at the register and swipe products across the scanner. I'm trying to figure out a way to remove the person from the equation.

Is there an easy way to simulate input FROM the serial port?

Obviously, sending information TO the serial port is easy:

echo [whatever] > /dev/ttyS2

but what I'd really love is some sort of bash code where I could type:

echo [barcode number] > (some code that makes the machine think the barcode number is coming from the serial port)

Is this possible?

I'm also restricted in what I can actually put on the register. I can't install any new utilities onto the machine. I can put bash scripts on there, but that's about it.

What about hardware? You can easily make a serial port loopback device (connect TX to RX), plug it into the serial port, and then anything you echo out the serial line would be immediately returned.

Unfortunately, the whole point of this exercise is to remove the need for anything to be done physically at the cash register. The idea is to be able to ssh into the register remotely and perform test scans without actually using the scanner.