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HECI and the previously used SMBus have the following aspects in common: the Host OS is able to control system management devices such as: on-board fan controllers, remote wake devices such as Wake-on-LAN, power supply devices such as Smart Battery Data. On the other hand, the inflexibility is even greater with HECI due to coupling HECI with a chipset, and having to redevelop HECI software for each different chipset as opposed to one common BMC software for multiple chipsets. High product lifecycle costs are incurred due to the non-standard implementation, which increases software and hardware design and validation costs while remaining relatively inflexible to future changes. High BOM costs are usually incurred due to the need for additional components and routing. These solutions typically suffer two main disadvantages due to their proprietary nature. Original equipment manufacturers ( OEMs) have historically provided active management technologies through the use of proprietary on-board controllers, such as Baseboard Management Controllers. The bus consists of four wires: a request and grant pair along with a serial transmit and receive data pair. This bi-directional, variable data-rate bus enables the host and ME to communicate system management information and events in a standards-compliant way, essentially replacing the System Management Bus (SMBus). The HECI bus allows the host operating system (OS) to communicate directly with the Management Engine (ME) integrated in the chipset.
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