ATT 6400 typewriter and PC6300 computer interface

[Graham Brand]

A friend of mine has one of the ATT 6400 typewriters (made by
Olivetti, I think) and has been using it as a letter quality
printer with his 6300 and the computer interface. 
	In general, the setup works quite fine but there are a couple
of annoying idiosynchracies which he has asked me to query for him.
Unfortunately, the it has been virtually impossible to get much 
information from ATT Data Systems as they all cry ignorance since
the typewriter was actually assembled by Olivetti. As you can guess,
Olivetti doesn't know anything either since the unit was marketed by
AT&T!
	The two annoying things are:
1. When using the printwheel that is supplied with the interface, the
   OCR615, certain keys print different characters. In particular, the
   underline character is different. Does anyone know which printwheel
   matches the keyboard?
2. I believe that the OCR615 is a 10 pitch Pica type. Does anyone know
   what the correct wheel for a 12 point Courier would be? While I am
   at it, how about a 12 point Pica and a 10 Point Courier as well?
   For all of these, it is necessary for the keyboard to match the
   printwheel. 

In case you are going to suggest buying any old printwheel from a
computer store, my friend has tried that and even more keys are wrong!!

Cheers,
-Graham