Need my 2.4ghz band on b/g/n standard

I have an XFINITY provided Gateway XB7.

user_o5zy6x Wireless B is not supported, that is the only hiccup. If you are needing something that supports an older band like B, you would need to run a separate wireless router dedicated to that device. 

Thank you for the clarification.  Would you be able to provide a link to any support that provides instructions on setting up an access point through my current gateway?  I don’t want to change the current Gateway or use the Bridge option, just possibly add an Access Point that supports b/g/n.

@user_o5zy6x To add an access point (AP) to your Xfinity modem (gateway), you'll generally connect a wired AP to a LAN port on the gateway, then configure the AP (often by putting it in Access Point Mode or disabling its DHCP/NAT) to avoid network conflicts (double NAT), using the same SSID/password for seamless roaming or different ones for distinct coverage, often facilitated via the Xfinity app for Pods or manual setup for third-party devices like Ubiquiti/UniFi. If you need access to the Admin tool, please make sure to go into your Xfinity App to enable access.

Option 1: Using Xfinity WiFi Extenders (Pods) Purchase Xfinity WiFi Extenders (Pods) from Xfinity. Open the Xfinity app, go to the Account tab, find Devices, and select "Activate WiFi Extenders". The app guides you to place and activate the Pods, which automatically extend your Xfinity network. 

Option 2: Adding a Third-Party Access Point (Wired Backhaul) - Run an Ethernet cable from a LAN port on your Xfinity gateway to the Ethernet/WAN port on your new AP. If your AP has an "Access Point Mode," enable it in its settings (often in the router settings under Network/LAN). If no AP mode, log into the AP's settings, disable its DHCP server, and assign it a static IP within your Xfinity network range (e.g., 192.168.1.x). Configure the AP's Wi-Fi with the same SSID (network name) and password as your Xfinity gateway for seamless switching, or a different name for a separate network. Some advanced APs (like UniFi) use Power over Ethernet (PoE), requiring a PoE injector or switch. 

Option 3: Bridge Mode (Advanced) This turns your Xfinity gateway into just a modem, letting your AP handle all routing. Connect the AP's WAN port to the Xfinity modem. Configure your AP (e.g., Orbi, UniFi) in its normal router mode to manage your network.