Hi Darkstar,

you got me interested in magazine printer buffer projects, and I was able to find a couple:

one in https://archive.org/details/radio_electronics_1985-09/page/n67/mode/2up

but unfortunately doesn't include any rom listings.

I did find one in Byte Magazine that did have a z80 rom code listing (it's really short, only about 100 bytes)

https://archive.org/details/byte-magazine-1984-06-rescan/page/n143/mode/2up

(part 2 of the article)
https://archive.org/details/byte-magazine-1984-06-rescan/page/n455/mode/2up

[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]