How do I check my Zoom 3G/4G Router's firmware revision?

Unplug any USB modem that is connected to the router. Also unplug any cable that is connected to the router's WAN port.
Connect a computer directly into the router via the LAN port or via wireless-N.
For Zoom router model 4501, 4506AG, or 4506BG: Open a web browser and type http://192.168.1.1 (the router's default LAN IP address) in the address bar. Press Enter.

For Zoom router model 4504: Open a web browser and type http://192.168.2.1 (the router's default LAN IP address) in the address bar. Press Enter.
When the USER's MAIN MENU page appears, type admin in the System Password field at the top of the page, and then click Login.
Click the Advanced icon at the top of the page.
Click the Toolbox icon.
On the Toolbox page, in the left column, click Firmware Upgrade.
The current firmware revision will be shown on the Firmware Upgrade page.