Here is how the connection was described in a different discussion:
https://groups.google.com/forum/#!to...ch/CJwcCaeZV9M
I have a 1992 TREK 970 frame with top tube cable routing. There is a cable
housing stop for the front derailleur on both ends of the top tube. There is
no other stop before the cable housing reaches the front derailleur but there
is an anchor bolt beyond it on the bottom bracket shell just below the
chainstays.I have a picture of the built up bike and it appears the cable & housing goes
from the rear stop on the top tube to all the way to the front derailleur,
beyond that only the cable extends through the derailleur and appears to anchor
on the bolt down on the bottom bracket. The front derailleur does appear to
have some kind of housing stop on it.