Hi friend!
You can associate it with 802.11n AP if the AP does not set the 802.11n-only mode. However,
the signal transmission rate of the APs in 802.11b mode is low. In contrast, the time that the
802.11n APs take to transmit radio signals at 300 Mbit/s accounts for only 1/27 of the time
that the 802.11b APs take to transmit radio signals. Therefore, when a comparatively large
number of old wireless terminals are connected to the 802.11n APs, the AP performance
decreases considerably. To ensure high performance of the entire WLAN, the 802.11b STAs
will be disabled to access the network.
Hope to help you!