The Toshiba Broadband (3G HSDPA) SM-Bus Minicard Modem driver is a software component required for enabling a Toshiba laptop or device to use a 3G HSDPA (High-Speed Downlink Packet Access) mobile broadband modem that connects to the internet via cellular networks. The SM-Bus Minicard refers to a type of small form-factor card (often an ExpressCard or Mini PCIe card) that fits into the laptop's internal bus, allowing it to interface with mobile broadband networks.

If you have a Toshiba laptop that came with this 3G HSDPA mobile broadband card, it uses the driver to communicate with the Windows operating system, allowing you to connect to the internet over mobile networks.