“Modem only” or “Bridge Mode” allows you to use the BT router as a connective bridge between your BT Business Broadband and your own router.
Fibre to the Premises (FTTP) customers - “Modem only” or “Bridge Mode” doesn’t apply, as you can simply plug your own router directly into the Optical Network Terminal (ONT) provided during your installation.
Non-FTTP customers - "Modem only” or “Bridge Mode” is not currently supported on the BT Business Smart Hub 3 so you’ll be unable to use your own third party router at this time.
Using your own router or a BT Business hub (other than the Smart Hub 3) in “Modem only” or “Bridge Mode” will mean you’re unable to make use of the added extras provided with your BT Business Broadband including Hybrid Backup, Complete WiFi or WiFi security features. In order to take advantage of these products you must use the BT Business hub supplied with your connection.