IBM T40 Internal Modem

The driver for the part of internal modem is loadable from snd_intel8x0m module. To create a modem device, download slmodemd which creates a node at /dev/ttySL0 for the modem which later can be used for the connection via PPP. Enable alsa mode (README) when installing slmodemd.
To run:

modprobe snd_intel8x0m
slmodemd --alsa hw:1