Someone from LinuxManagers suggested "VtPrint" for pass-thru printing in vt100 at the Linux text mode console. This web page says that vtprint can print vt100 and some other odd ball print codes.
http://garrett.damore.org/~garrett/software/vtprint/ Debian has packages of vtprint, but I haven't seen any RPM distributions. I don't know if this would do the job of what we need for the Linux cash registers.
