As there are a number of these printers STILL popping up on ebay and such-like, I thought I would resurrect this post.
The TM-C600 seems, though I can't be 100% sure, to be a special order machine, manufactured by Epson exclusively for Catalina Marketing. That is the reason we're not finding drivers for it - because they were never made publically available, as the printers were never designed to be used outside of a Catalina provided environment.
Epson TM printers are, generally, still current - and you'll find the majority of receipts you have printed from whichever stores you visit are coming from Epson TM printers - it's just their EPOS range, so usually you have to have some specialist or in-depth knowledge of these kinds of systems to get them to do something. More often than not, you don't use a driver, you communicated directly with the printer using codes sent down a physical serial link... remember THOSE days!?? LOL
Anyway - I'm working on getting a driver package working for the TM-C600 - and I've had some success - I have printing working, in colour, however more advanced features, like cutting, ink monitoring etc, do not yet work. If anyone is still interested, post back in here, and I'll keep the thread updated with progress.