State and CEntral Boards(SCB) Channel -  It is one of the channel through which you can get in to IISER (other channels being JEE and KVPY). Candidates opting for this channel have to write the aptitude test. Yes, SCB channel is only for the admission in different IISERs. The aptitude test is computer based 3 hours test of 180 marks comprising four subjects with equal weightage - physics, chemistry, mathematics and biology (15 MCQ type questions each).