I found RasCreatePhonebookEntry to create a phone book entry but in SDK its mentioned as "This function has been deprecated as of Windows Vista and its functionality has been replaced by RasDialDlg" So is there any other way to create a new phone book entry with out promting to the user which supports in all versions of Windows? And if RasCreatePhonebookEntry itself can be used for all versions of windows to create a new phone book entry, how to set the value of "Preferred COM port" option using "RASENTRY" structure? I didnt find any parameter in RASENTRY STRUCTURE to set the preferred port.. I want to set the following parameters in phone book : PreferredPort=COM31 PreferredDevice=Communications cable between two computers #5 MEDIA=serial Port=COM10 Device=Communications cable between two computers #5 ConnectBPS=460800 How to set the above parameters programatically by creating a new entry in phone book.