Which digital subsystem converts coded input characters (for example, BCD or 7-bit ASCII) into a human-readable or device-usable form such as segment drives or control lines?

Introduction / Context:
Code translation is pervasive in digital electronics. Systems often produce compact coded representations (e.g., BCD, Gray, ASCII) that must be translated into a format understood by displays or actuators. Knowing which block performs this conversion is foundational.

Given Data / Assumptions:

• Input is a coded representation of information.
• Output should be a more intelligible form (e.g., seven-segment lines, control signals, or readable symbols).
• Focus on functional role, not a specific IC part number.

Concept / Approach:
A decoder maps coded inputs to a set of outputs representing the decoded meaning. Examples include BCD-to-7-segment decoders that translate a 4-bit BCD value into seven segment drive lines, or address decoders that convert binary addresses into one-hot select lines for memory chips. Encoders perform the opposite transformation, compressing many inputs into a code.

Step-by-Step Solution:
1) Identify data form: coded inputs.2) Determine desired output: human-readable or device-specific drive signals.3) Functional mapping: decoder expands or translates code to meaningful outputs.4) Conclude that the correct subsystem is a decoder.

Verification / Alternative check:
Common ICs like BCD-to-7-seg decoders (e.g., classic parts) exemplify this function, turning numeric codes into display segments that humans can read.

Why Other Options Are Wrong:
Encoder: opposite function (many inputs to fewer coded outputs).

Display: a sink device; it does not perform the translation.

Counter: produces sequences; no code translation implied.

Latch: stores state; does not translate codes.

Common Pitfalls:
Assuming displays inherently decode; they only render signals they receive. The decoder must drive them correctly.

Final Answer:
decoder