Failed?

Yesterday after dinner I noticed that this had stopped working correctly, any ideas what it is?

Earlier this week I ordered some new bits to upgrade my better half's computer. Today my 15 year old Epson printer was really badly behaved. I don't print all that often and always said once it dies I'll replace it with a networked mono-laser printer which would be much more useful. Today it was really badly behaved and I think it's time to replace it. Annoyingly I paid extra for an old parallel port to connect to this printer, which will be redundant if I go wired networking instead! BTW today's mystery blip isn't from a computer or a printer...