Discrete I/O modules can be classified as

• A. Bit oriented
• B. Byte oriented
• C. Word oriented
• D. Nibble oriented

Answer: (A)

Discrete I/O modules are built to carry binary signals—on or off. Because each channel represents a single binary state, they’re described as bit oriented. A discrete input reads one bit per channel for each sensor, and a discrete output drives one bit per channel for each actuator. The idea here is that the data is managed at the level of individual bits rather than grouped into larger data units. Byte-oriented or word-oriented classifications would imply handling 8-bit or larger chunks of data, which is more typical for data that represents numbers or multiple related signals rather than single binary I/O points. Nibble oriented would mean grouping into 4-bit units, which isn’t how discrete I/O is standardly categorized.