Please follow the steps below:
1. Check fom Android phone(some phones may be different)：
Enter mobile phone to connect to Wi-Fi, after the connect successful, click to view the details, you can see the Wi-Fi signal frequency:
2. Check from Window，follow these steps:
a. Click the network logo in the lower right corner of the system desktop, in the pop-up box, click [Properties].
b. In the window that opens, look at the "Properties" item. You can see that [Network Band] is 2.4G, which means that the wireless router network I use is 2.4G band, as shown below:
3. Check from Mac：
Click on the wireless networking icon at the top of the screen while holding down the Option key.
