Such data is highly guarded by companies, often because it can be
embarrassing. It certainly was when I did QA stuff at USR (you know, doing
real life manufacturing engineering, instead of sitting in my parent's
basement).
Hmm.. I have a USR modem here. It's been fine for many years _after_ I
resoldered a lot of dry joints shortly after I got it (on the PCB and on
the secodnary of the transformer in the mains adapter). Oh, and
re-crimped the telephone plug.
So to be honest, I don't think much of USR prodcution or quality control.
-tony