You could then hook your notebook modem (whose drivers are ususally part of the sound card, AC'97 oder HDA) and get, albeit slow, some internet, if you are desperate
Over here, you are more likely to find ISDN than analogue so you'd be stuck with the modem anyway.
I'd rather recommend getting a UMTS adaptor (PCMCIA/PC card or USB) if you need to rely on internet.
As long as you have cell phone connection (you could of course also pair your phone via Bluethooth), you should be fine.
Personally, I think still putting a modem into a modern notebook is a waste of space and resources.
While it may not cost much to implement (they are most likely win modems I guess), it serves no real puprose anymore.
Some 10 years ago that may have been different, but times have changed rapidly!