A.74167-Synchronous Decade Rate Multipliers B.74166-Parallel Load 8-Bit Shift Register C.74165-Parallel Load 8-Bit Shift Register D.74164-8-Bit SerialIn/Parallel Out Shift Registers
A.CD4069 B.74LS232 C.ICL232 D.74HCT244
A.较高的电压准位 B.差动讯号模式 C.半双工传输 D.PCM编码