Source : Free On-Line Dictionary of Computing

System Management Bus
     
         (SMBus, SMB) A simple two-wire {bus} used
        for communication with low-bandwidth devices on a motherboard,
        especially power related chips such as a laptop's rechargeable
        battery subsystem (see {Smart Battery Data}).  Other devices
        might include temperature sensors and lid switches.
     
        A device can provide manufacturer information, indicate its
        model/part number, save its state for a {suspend} event,
        report different types of errors, accept control parameters,
        and return status.  The SMB is generally not user configurable
        or accessible.
     
        The bus carries clock, data, and instructions and is based on
        {Philip's} {I2C} serial bus protocol. Support for SMBus devices
        is provided on {Windows 2000}. {Windows 98} does not support
        such devices.
     
        The {PIIX4} {chipset} provides SMBus functionality. Vendors
        using SMBus would be required to pay royalties.
     
        {SMBus website
        (http://www.sbs-forum.org/smbus/)}.
     
        {Software to interrogate a SMB motherboard
        (http://www.online.de/home/podien/SMB.HTM)}.
     
        {SMB devices, Part 8 Kernel Mode Driver Design Guide, Win2000 DDK
        (http://www.microsoft.com/ddk/)}.
     
        (1999-08-08)