1st interview is by phone, conducted by the HR Recruiter assisting the hiring manager. Takes about 15-30 minutes analyzing your resume, along with seeing how it ties to the job description posted. Ensure to mirror your resume to your job description, where there are similarities.
2nd interview is on-site with the hiring manager, along with his/her peers (managers they work with). Each asks their own line of questions, and lasts between 30 minutes to 1 hour. They will have your resume for review, and they will cross-check to ensure they way you communicate match and coincide with what you stated in your resume. They will be able to catch any "misleading" skill-sets written in your resume, so be prepared to explain what you did at your current/former workplace to justify why you put that in your resume.