03 July 2013
1) 143(2) - It is a notice issued by the IT department to produce documents/ books of accounts ,in support of the return filed, for verification.
2) 143(3) - It is an assessment order passed by the ITO after verification as aforesaid.
3) 153A - It is a notice issued by the AO, consequent to search cases, to file return s for six years preceding the search.
The circumstances for i and 2 above occurs when the case is selected for 'scrutiny' and the 3rd after 'search' conducted by IT department.