In a start - stop teletypewriter system , the significant condition of the signal element that immediately precedes a character signal or block signal and prepares the receiving equipment for the reception of the code elements 在啟動(dòng)一個(gè)電傳打字機(jī)系統(tǒng)中,迅速領(lǐng)先字符信號(hào)或閉塞信號(hào),并且準(zhǔn)備好接收設(shè)備為接收代碼元件的信號(hào)元件的有效狀態(tài)。