150 ï GlossaryWAGO-I/O-SYSTEM 750DeviceNet7 GlossaryBit Smallest information unit. Its value can either be 1 or0.Bitrate Number of bits transmitted within a time unit.Bootstrap Operating mode of the fieldbus Coupler / Controllers.Device expects a firmware upload.Bus A structure used to transmit data. There are twotypes, serial and parallel. A serial bus transmits databit by bit, whereas a parallel bus transmits many bitsat one time.Byte Binary Yoked Transfer Element. A byte generallycontains 8 bits.Data bus see Bus.Fieldbus System for serial information transmission betweendevices of automation technology in the process-related field area.Hardware Electronic, electrical and mechanic components of amodule/subassembly.Operating system Software which links the application programs to thehardware.Segment Typically, a network is divided up into differentphysical network segments by way of routers or re-peaters.Server Device providing services within a client/server sys-tem. The service is requested by the Client.Subnet A portion of a network that shares the same networkaddress as the other portions. These subnets are dis-tinguished through the subnet mask.