A.噪聲容限為±(3~5)VB.當(dāng)輸入端開路時(shí),終端定為空號(hào)C.控制線的接通狀態(tài)規(guī)定為-3~-15VD.數(shù)據(jù)“1”(“傳號(hào)”)規(guī)定為+3~+15V