Informix and MS Access

Hello!! I have been browsing through the FAQ and could not find an exact asnwer to my question.. I am interested in having Informix and MS Access interact with each other. I will be using MS Access (as my user interface)to view information as well as enter new information. My informix database has the following characteristics: Online dynamic server (version 7.1). We also have I-Net (version 5.01). I have contacted Informix and they gave me the names of 2 companies that sell ODBC drivers for Informix: Intersolve and Visigenic. I contacted Visigenic and they asked me for the API levels needed... Core, level 1 or level 2? Does anyone know exactly what they mean? Maybe refer me to a reference document? I would like to know if the communication between Access and Informix is good. If the information sent is accurate and if there are errors or problems that other users have faced. Also, if previous users have other suggestions or other ODBC drivers that I could use? Thank you very much for your help!!