問題文
An office is replacing very old equipment and finds a wireless bridge which advertises support for the 802.11a physical layer alone. Which statement about that device is correct?
選択肢
- It runs OFDM in the 5 GHz band with a 40 MHz channel and reaches a data rate of 150 Mbps for each spatial stream it uses.
- It runs HR-DSSS in the 5 GHz band with a 22 MHz channel and reaches a data rate of 11 Mbps at best anywhere inside the school building.
- It runs OFDM in the 2.4 GHz band with a 20 MHz channel and reaches a data rate of 54 Mbps which also lets it serve the older scanners in the school.
- It runs OFDM in the 5 GHz band with a 20 MHz channel and reaches a data rate of 54 Mbps at best there.