[37C. Service of decisions, orders, summons, etc.--(1) Any decision or order passed or any summons or notices issued under this Act or the rules made thereunder, shall be served,--
(a) by tendering the decision, order, summons or notice, or sending it by registered post with acknowledgment due [or by speed post with proof of delivery or by courier approved by the Central Board of Excise and Customs constituted under the Central Boards of Revenue Act, 1963 (54 of 1963)], to the person for whom it is intended or his authorised agent, if any;
(b) if the decision, order, summons or notice cannot be served in the manner provided in clause (a), by affixing a copy thereof to some conspicuous part of the factory or warehouse or other place of business or usual place of residence of the person for whom such decision, order, summons or notice, as the case may be, is intended;
(c) if the decision, order, summons or notice cannot be served in the manner provided in clauses (a) and (b), by affixing a copy thereof on the notice-board of the officer or authority who or which passed such decision or order or issued such summons or notice.
(2) Every decision or order passed or any summons or notice issued under this Act or the rules made thereunder, shall be deemed to have been served on the date on which the decision, order, summons or notice is tendered or delivered by post [or courier referred to in sub-section (1)] or a copy thereof is affixed in the manner provided in sub-section (1).]