 Those exceptions include messages addressed to the I2C "general call" address (0x00) or to the SMBus "Alert Response Address"; and messages involved in the SMBus "Address Resolution Protocol" (ARP) for dynamic address allocation and management.In practice, most slaves adopt request-response control models, where one or more bytes following a write command are treated as a command or address.Those bytes determine how subsequent written bytes are treated or how the slave responds on subsequent reads.