The Free On-line Dictionary of Computing (30 December 2018):

System Management Bus
SMBus

    (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://sbs-forum.org/smbus/).

   Software to interrogate a SMB motherboard
   (http://online.de/home/podien/SMB.HTM).

   SMB devices, Part 8 Kernel Mode Driver Design Guide, Win2000 DDK
   (http://microsoft.com/ddk/).

   (1999-08-08)