We are working on switching our POS registers to Ubuntu from Windows. Our registers run in a WAN configuration so the POS software doesn't actually run on them but rather is running on a Windows server and is served to them through Citrix Receiver. We have our devices set in the POS software on the server to specific COM ports. When a register connects the server maps up the COM ports/devices on that machine and talks to those devices on specific COM ports. Specifically COM4 for receipt printer and COM5 for credit card reader. Both are USB devices emulating COM ports.

I've already made the user part of the dialout group and found the tty devices in the /dev folder.
What do I need to do tell ttyAMC0 to identify itself as COM5?


You need to create a new UDEV rule to make sure the software always points to the correct port.

Go to /etc/udev/rules.d and create a file named "COM5.rules"

Edit the file and put the following line in it. The id's (067b) and (2303) must be replaced by the id's from your hardware.

SUBSYSTEM=="tty", ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", SYMLINK+="COM5"

After reboot a device called @COM5 will be created in /dev Set the software to go to /dev/COM5

Rebooting or taking out the port and installing it again even updating, upgrading and even major version upgrades of the whole system, it all stays persistent.

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