Yesterday I received a Fire 7 (9th Gen) Tablet. According to the official datasheet, it supports dual-band 802.11n Wi-Fi. To my surprise, the SSID of my 5GHz Wi-Fi router didn't show up. After talking to support it was explained to me that the device only supports the channels 36, 40, 44, 48 on the 5GHz band. At the same moment, my router doesn’t allow me to specify the channel it is using.
So I talked to both support staff for the tablet and the router. The ISP who is the provider of my router is stated:
It's the tablet's fault it should be able to scan on all channels. Other devices can connect on the 5GHz band without problems.
The Amazon support, on the other hand, stated:
It’s the router's fault, it should be able to specify the channel it is using. The tablet can connect to other 5GHz Wi-Fis without problems.
So my question is: Which device violates the 802.11n protocol standards? Or is it totally valid that two devices which both support 802.11n on the 5GHz band aren’t able to connect?