The submission of I4U, is a joint effort of nine research Institutes and Universities across 4 continents for submitting speaker recognition results to NIST SRE 2012. The joint efforts were started with a brief discussion during the Odyssey 2012 workshop in Singapore. An online discussion group was soon set up afterwards, providing a discussion platform for different issues surrounding the NIST SRE’12. In particular, noisy test segments, uneven multi-session training, variable enrollment duration, and the issue of open-set identification have been actively discussed. Various solutions were put in place as part of the I4U submission. The submission of I4U as well as several individual submissions from coalition members, was found to be among top-performing systems submitted to SRE’12. This paper summarizes the system components’ details for 17 systems included in I4U submission.