tar xvzf pctel-0.9.4.tar.gz
cd pctel-0.9.4
./configure --with-hal=i81x --with-kernel-includes=/usr/src/linux-2.4.18-17.7.x/include/
make
# assume root identity. It is not enough to type su from a generic user
# since it may have not the correct environmet settled.
make install
# add to /et/rc.local the two lines
/sbin/modprobe pctel
/sbin/modprobe ptserial