The interface is a connection and interaction between hardware,software and the user.Hardware interfaces are the plugs,sockets,wires and the________(电脉冲)traveling through them________a particular pattern.Also included are electrical timing considerations.Examples________RS________232 transmission,the Ethernet and Token Ring network topologies and the IDE,ESDI,SCSI,ISA,EISA and Micro Channel interfaces.Software interfaces are the languages,codes and messages programs use________communicate with each other and to the hardware.Examples are the applications that run under the Mac,DOS and Windows operating systems________the SMTP e________mail and LU 6.2________(通信协议).User interfaces are the keyboards,mice,commands and menus used for communication between you and the computer.Examples are the command lines in DOS and UNIX,and the Mac,Windows and Motif________(图形界面). Interfacing is a major part of what________(工程技术人员、程序设计人员和咨询人员)do.Users“talk to”the software.The software“talks to”the hardware and other software.Hardware“talks to”other hardware.All this is interfacing.Every interface________(暗含着 一种结构).Electrical signals are made up of________(电压电平、频率和持续时间).The data passed from one device or program to another has a precise format(header,body,trailer,etc.).Every interface implies a function.At the________level,electronic signals activate functions;data are________,written,________,received,analyzed for error,etc.At the software level,instructions________the hardware(access methods,data link protocols,etc.).At higher levels,the data transferred or transmitted may itself request functions to be performed(client/server,program to program,etc.).