This does not sound like it would be a Linux issue, but an issue with your iface402. It looks like it is supposed to connect to a serial printer and work, and I don't see any indication from their site or their user manual that you are able to go in and manually troubleshoot the printing system.
You probably need to contact their customer support.
Unless you are able to get to a Linux shell, and actually configure the system? I don't see anything about that in their manual. Could you point to some online documentation regarding what you are trying to do?