(a) Before a board is convened under section 2106 of this title, notice of the convening date, the promotion zone to be considered, and the officers eligible for consideration shall be given to the service at large.

(b) Each officer eligible for consideration by a selection board convened under section 2106 of this title may send a communication through official channels to the board, to arrive not later than the date the board convenes, inviting attention to any matter of record in the armed forces concerning such officer. A communication sent under this section may not criticize any officer or reflect upon the character, conduct, or motive of any officer.