Thank you to all but my question was more on how to make or buy a cheap
and not necessarily versatile piece of hardware.
If I find it, a second hand B&G could be the answer but I was thinking
more of a DIY (or Do-It-Myself would be more appropriate...) box with
few smart chips and a non graphic LCD display. Any of you guys ever
bumped on something similar?

Peter, I have known your site for years and I still appreciate it
whenever I need information on NMEA.

Daniel