A serial transmission Ti uses 8 information bits, 2 start bits, 1 stop bit and…
2004
A serial transmission Ti uses 8 information bits, 2 start bits, 1 stop bit and 1 parity bit for each character. A synchronous transmission T2 uses 3 eight bit sync characters followed by 30 eight bit information characters. If the bit rate is 1200 bits/second in both cases, what are the transfer rates of Ti and T2?
Answer: C. 100 characters/sec, 136 characters/sec — Compute the transfer rates step by step: Serial transmission (T1): Bits per character = 8 information + 2 start + 1 stop + 1 parity = 12 bits. Characters per…
- A.
100 characters/sec, 153 characters/sec
- B.
80 characters/sec, 136 characters/sec
- C.
100 characters/sec, 136 characters/sec
- D.
80 characters/sec, 153 characters/sec
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Correct answer: C
Compute the transfer rates step by step:
Serial transmission (T1):
Bits per character = 8 information + 2 start + 1 stop + 1 parity = 12 bits.
Characters per second = 1200 bits/s ÷ 12 bits/character = 100 characters/sec.
Synchronous transmission (T2):
Frame composition: 3 sync characters + 30 information characters = 33 characters per frame.
Total bits per frame = 33 × 8 = 264 bits.
Each frame carries 30 information characters, so effective information characters/sec = 1200 bits/s × 30 characters / 264 bits ≈ 136.36 → approximately 136 characters/sec.
Final answer: serial transmission = 100 characters/sec; synchronous transmission = 136 characters/sec (approx).