Is gateway capable of 2.4vGHz also?

Hey so I am really new here and also technologically stunted. Anyways I got like a security system and it operates on 2.4GHz which it keeps saying it is not able to link with my Wi-Fi. So I'm going to assume mine is currently on 5G. I was reading other things and they said I could make my router do that. I have the gateway thing that like you can just get with from xfinity. Does anyone know if it is possible to make it do both? Or if that isn't an option what do I do?