如果要求输入的 0 字符，只返回输入缓冲器内没有处理的字符数。 如果终止字符不在输入缓冲器，操作的状态为未完成，直到收到终止字符或 超时间隔终止。在任何一个这些条件内，接口状态指示读操作完成的原因。. 如果超时间隔设定为 0，COMMREQ 悬而未决直到它已经收到请求的列

ALLEN BRADLEY 2711-K3A10L1 Series A Revision C FRN 4

SCHNEIDER AUTOMATION AS-HDTA-202 SECONDARY SUBRACK NIB

IDC CORPORATION RDC-045805 MODEL SH21

CROUSE-HINDS WSRD63542 INTERLOCKING PLUG NON-FUSIBLE DI

BALDOR M7032T HAZARDOUS LOCATION AC MOTOR, FRAME 145T,

ARO INGERSOLL-RAND BARREL PUMP

GOODYEAR 569-012-254-002?00 HORIZON AIR & MULTI-PURPOSE

GENERAL ELECTRIC CR308D1021EXAA SIZE 2 COMBINATION STAR

SEW EURODRIVE RF87AM184 HELICAL GEARMOTOR, RATIO 72.57:

SEW EURODRIVE RF87LP256 HELICAL GEARMOTOR, RATIO 7.12:1

SEW EURODRIVE S67DT90S4BH62HR?TH1S HELICAL-WORM GEARMOTO

SEW EURODRIVE K77DV100L4BM64H?FTH1S HELICAL-BEVEL GEARMO

SEW EURODRIVE KH47DT80K4BMG05?HR6R15 HELICAL-BEVEL GEARM