On the Internal modem, take the output of the command:
/sbin/lspci
write down the info about the modem and feed it into
www.google.com/linux or look it up on
www.linmodems.org. USR or maybe the chipset is Lucent and a lot of others have working drivers for winmodems out there... the odds are rather long, but they tend to work when they claim to: did on my laptop!
On the external, as root:
/sbin/modprobe serial
dmesg
See if there's some info about the kernel having seen the modem, it'll be at the end. Then either install or more likely just start the application kppp, its a pretty good dialer utility.
Cheers,
Finegan
P.S. Always avoid tagging a thread with Urgent, its sort of the forum equivalent of "ignore me"