In anna university counselling application, in place of HSC Equivalent registration number, you are supposed to fill your HSC/12th Board roll number/ registration number. If you check your marksheet or just the result page on the website, you will see your registration number there. You are supposed to fill that number only.

Hi Camella.hsc register number is nothing but your roll number what is placed on the top of the mark sheet.it is your registered roll number.you could know this very well as your are placed seating according to your registered roll number wise.just view the top of the paper which is your registered roll number.all the best!!