Assume that each character code consists of 8 data bits and is framed for…

Concept: In asynchronous serial transmission there is no shared clock between sender and receiver, so every character is framed on the line: one start bit marks where the character begins and one or more stop bits mark where it ends. Those framing bits occupy line time exactly as data bits do, so the useful character rate is the line's bit rate divided by the total number of bits in one complete frame — never by the number of data bits alone. On a line that carries one bit per signalling element, the baud rate is numerically equal to the bit rate. If parity is enabled, one parity bit is also added; otherwise no parity bit contributes to the frame length.

1. Frame size on this line = 1 start bit + 8 data bits + 2 stop bits = 11 bits per character.

2. Line bit rate = 2400 baud = 2400 bits per second, since one bit is carried per signalling element.

3. Characters per second = bit rate / frame size = 2400 / 11 = 218.18.

4. Only whole characters are actually delivered within one second, so the count is 218 characters per second.

Cross-check: 218 complete frames occupy 218 × 11 = 2398 bits, which fits inside the 2400-bit budget of one second, while 219 frames would need 219 × 11 = 2409 bits — more than the line can carry in a second. Contrast: dividing by only the 8 data bits gives 2400 / 8 = 300, the rate a line with no framing overhead would reach; the start bit and the two stop bits are exactly what reduce it.