フリー問題

問題文

An engineer is comparing what the frame check sequence at the end of an 802.15.4 frame can do with what forward error correction can do. Which pair states the reach of each mechanism?

選択肢

1. The two mechanisms stop at different points, so the trailing checksum repairs the damaged frame and the added redundancy restores the lost bits in that specification.
2. The two mechanisms stop at different points, so the trailing checksum identifies the damaged frame and the added redundancy restores the lost bits in that specification.
3. The two mechanisms stop at different points, so the trailing checksum repairs the damaged frame and the added redundancy reports the lost bits in that specification.
4. The two mechanisms stop at different points, so the trailing checksum identifies the damaged frame and the added redundancy reports the lost bits in that specification.