Finding a land line number for some one you are skip tracing is about as likely as hitting Powerball these days. Even if you find a land line number, most of the time they are old numbers or only used by the elderly. Most of the time you are going to find a cell phone number. Some skip traces will immediately go and find a pay for phone number site and punch the number in and get the address. More diligent skip tracers (me) will do more research. There are several websites you can search to find out more information, such as Fone finder.
Fone Finder is a free, public search engine that finds the geographic location of any phone number in the world. You key in a phone number, and it will give you the city, state, country, a flag, map, and links to the area. Fone Finder can also find the country code, area code, and prefix given the city name. You can always find the international country given a phone number. For a growing list of countries, including the USA, Mexico and Canada, Fone Finder will also find the city.
Or TNID, which is simply telephone number id. This gives you very similar information to Fone Finder. This includes the following information,
Original Telephone Company, Original Telephone Company Type, Estimated City, Estimated Region, Estimated Postal Code and Equipment Location Code.
If these do not work you can contact pay websites. I personally used the one used by the Police in my area. It is call TLO.com