Non Project specific Interview will mostly ask about details in your resume and general questions on the subject you are applying for or the your skills. Sometime and more often, a business scenario and how you will apply. Project specific interviews are specific and still relevant to the info in your resume. More detailed and mostly around your experience of your application in other projects for that subject/module. One can expect a lot of checks for experience with WRICEF, Idocs, Interfaces apart from the core module.