Well, my friend still hasn't posted it, so here goes for prosperity.
In NASCAR2, you go to modem, custom setup, and start entering a long
string and NOPE, it only allows a certain number of characters. This
was shorter than the string my friend has used for NASCAR and ICR2, and
was only 1 or 2 characters more than what I have been using. We did
manage to get the link to work by removing one non-needed command, but
why limit the string to barely the average string? Hope Papy can
increase this limit in the "Upcoming patch". This one really should be
easy. That's all.