Hi Jin,
these numbers (RxQual) correspond to the estimated bit error rate:
0: BER is less than 0.2 percent
1: BER between 0.2 percent AND 0.4 percent
2: BER between 0.4 percent AND 0.8 percent
3: BER between 0.8 percent AND 1.6 percent
4: BER between 1.6 percent AND 3.2 percent
5: BER between 3.2 percent AND 6.4 percent
6: BER between 6.4 percent AND 12.8 percent
7: BER greater than 12.8 percent
Regards,
Rex