Even parity framing — location of the parity bit In a typical asynchronous serial frame using even parity, where is the parity bit positioned relative to the data bits?

Introduction / Context:
Parity is often used in asynchronous serial communication (e.g., UART) as a lightweight error check. Frames are typically structured as: start bit → data bits (LSB first) → optional parity bit → stop bit(s). Understanding the position of the parity bit helps in configuring serial ports and interpreting waveforms.

Given Data / Assumptions:

• Even parity scheme (total number of 1s across data + parity is even).
• Standard UART-style asynchronous framing.
• Data bits are sent least significant bit first.

Concept / Approach:
In UART frames, the optional parity bit is appended after transmitting all data bits. Because the line transmits LSB first, “after the LSB” refers to the parity bit coming after the entire data field in time (i.e., following the data bits portion). This convention is reflected in most serial hardware configurations (e.g., 8E1 for 8 data bits, even parity, 1 stop bit).

Step-by-Step Solution:

Verification / Alternative check:
Consult any UART frame diagram; parity, if enabled, appears between the data field and the stop bit(s), i.e., temporally after all data bits have been sent.

Why Other Options Are Wrong:

• Before the MSB: not the standard UART placement.
• In the parity word: parity is a single bit, not a separate word here.
• After the odd parity bit: irrelevant; parity type (even/odd) chooses bit value, not position.

Common Pitfalls:
Confusing frame bit order (LSB-first) with visual MSB-left diagrams; the parity bit follows the data field regardless of which end is considered MSB or LSB in diagrams.

Final Answer:
After the LSB