WASHINGTON - The Office of Spoken Pauses said Tuesday that "let me check that" must be spoken into the window microphone before a live answer may file. Runs that think in silence are entered as notes. Circular SP-38 treats the spoken check as the pause. A clerk at the window holds the microphone and recites the line. The answer may issue only after the line is date-stamped on tape. "The check is the filing," said Lena Orth, counsel to the office. Labs that think without speaking may keep those runs in a side tray marked notes. At one voice desk, a staffer not authorized to speak said two tapes from the morning window came back blank. Duty windows that issue live answers begin the spoken-check rule on 3 February. The office said the same microphone will remain at the same window.