and ask what you need ...
I guess, your hotel is providing a wireless connection (using ISDN instead of ADSL or Cable).. if this is the case .. then you don't need anything else.
I don't think you should need anything, except an ISDN adapter card... Which is not common device in many laptop.. Unless this device is available for renting .. which is unlikely..
so it is also unlikely if the guess have to carry ISDN adaptor, to use their service.
Just a thought.
Am thinking of taking my Dell Inspiron 6000 laptop to the UK for a brief time. Am already set up for home wireless network operation via cable modem & Linksys WRT54G router. Hotel I'll be staying at has only ISDN. What additional gear would I need for internet connection? Thanks a bunch for any and all help/advice.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic