The second was
a board that fitted in the optional interface slot in an HP
 LJ2 and others that used the same formatter). AFAIK, this was a
 third-party product, and I have never seen one. 
 I believe that that was what the JLASER interface was.  But Talltree is
 long gone.  I wonder if PrinterWorks would have access to such?  At least
 they would be the a good authority about what is/was available. 
 
I beleive that's where I heard about the CX-VDO interfce card that wrnt
in ther option slot of an LJ2 or similar.
The official one -- the one that replaces the formatter -- I have seen i
nthe flesh. It was in a friend's printer (which he used with an Acorn
Archimedes) that I had to repair. I had it on the bench for long enough
to trace out the schematic of the interface board, but I couldn;t get it
near the PERQ to see if it would work on that machine.
-tony