The CAT 2018 timeline is expected to be similar to that of CAT 2017. The official CAT 2018 notification shall be tentatively released on the last Sunday of July 2018. Online application for the exam shall remain open tentatively from second week of August to fourth week of September 2018. Likewise, the CAT 2018 exam can be expected to be held in the fourth week of November 2018.
There is Test System Number in your CAT Admit card. This unique number is provided for the purpose of identifying the floor / wing and your designated seat at the exam centre on the CAT exam date.
For any other correspondence with your CAT exam centre, you should provide your Registration Number and not the Test System number.