电话语音应答系统

要解决的几个关键问题
3.1设计中要解决的问题
要实现本系统，就必须用语音猫+vb解决以下几个问题：1.来电显示 2.来电应答  3.打电话 4.放音 5.录音 6.发短消息,7收发传真.
3.2 具体实现中采用的关键技术及复杂性分析
要能用语音猫来实现上述想实现的功能，我们首先要对语音猫和串行通信有着深刻的了解，同时要对语音猫的AT命令与TAPI函数要非常的了解，可能大家都要问，什么是AT命令呢？和人一样，人与人交流最主要是是用语言来交流，那么我们要和语音猫交流的话，就要我们人必须要懂语音猫能看得懂的AT命令。也就是说，语音猫只能看得懂AT命令。什么叫TAPI呢？TAPI是指与电话有关的API函数，下面我就列出了所有的TAPI函数。我进行CTI系统进行开发时，采用自上而下软件开发方法，一个大系统分成许多模块来开发的。也就是说，要实现一个大目标，我们把他分成许多个小模块来实现的。我把本系统为成了以下几个小模块：1.来电显示 2.来电应答  3.打电话 4.放音 5.录音 6.发短消息,7收发传真.下面就让我详细说明这些功能设计的步骤。
TAPI函数简介：
Option Explicit   所有变量都必须先定义后使用
Public Const LINEDIGITMODE_DTMF = &H2 copyright think58
‘线路为数字模式

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Public Const TAPIVERSION = &H10004
‘TAPI函数的版本号为:1.04
Public Declare Function lineMonitorDigits Lib "Tapi32" (ByVal hCall As Long, ByVal dwDigitModes As Long) As Long
Public Declare Function lineGenerateDigits Lib "Tapi32" (ByVal hCall As Long, ByVal dwDigitMode As Long, ByVal lpszDigits As String, ByVal dwDuration As Long) As Long
‘得到来电号码、来电时间等信息 
Public Declare Function lineGetCallInfo Lib "Tapi32" (ByVal hCall As Long, ByRef lpCallInf As lineCallInfo) As Long
‘电话线路初使化
Public Declare Function lineInitialize Lib "Tapi32" (ByRef hTAPI As Long, ByVal hInst As Long, ByVal fnPtr As Long, ByRef szAppName As Long, ByRef dwNumLines As Long) As Long
Public Declare Function lineNegotiateAPIVersion Lib "Tapi32" (ByVal hTAPI As Long, ByVal dwDeviceID As Long, ByVal dwAPILowVersion As Long, ByVal dwAPIHighVersion As Long, ByRef lpdwAPIVersion As Long, ByRef lpExtensionID As lineextensionid) As Long
‘打开电话线路
Public Declare Function lineOpen Lib "Tapi32" (ByVal hLineApp As Long, ByVal dwDeviceID As Long, ByRef lphLine As Long, ByVal dwAPIVersion As Long, ByVal dwExtVersion As Long, ByRef dwCallbackInstance As Long,  ByVal dwPrivileges As Long, ByVal dwMediaModes As Long, ByRef lpCallParams As Long) As Long think58好，好think58
Public Declare Function lineGetDevCaps Lib "Tapi32" (ByVal hLineApp As Long, ByVal dwDeviceID As Long, ByVal dwAPIVersion As Long, ByVal dwExtVersion As Long, ByRef lpLineDevCaps As linedevcaps) As Long
线路设置特定的状态信息
Public Declare Function lineSetStatusMessages Lib "Tapi32" (ByVal hLine As Long, ByVal dwLineStates As Long, ByVal dwAddressStates As Long) As Long
打电话
Public Declare Function lineMakeCall Lib "Tapi32" (ByVal hLine As Long, ByRef lphCall As Long, ByVal lpszDestAddress As String, ByVal dwCountryCode As Long, ByVal lpCallParams As Long) As Long
挂电话  
Public Declare Function lineDrop Lib "Tapi32" (ByVal hCall As Long, ByVal lpsUserUserInfo As String, ByVal dwSize As Long) As Long
挂电话，释放资源
Public Declare Function lineShutdown Lib "Tapi32" (ByVal hLineApp As Long)  As Long
应答电话
Public Declare Function lineAnswer Lib "Tapi32" (ByVal hCall As Long, ByRef lpsUserUserInfo As String, ByVal dwSize As Long) As Long
得到是哪一条线路正在使用，获得一个ID号 本文来自think58 [资料来源：www.THINK58.com]
Public Declare Function lineGetID Lib "Tapi32" (ByVal hLine As Long, ByVal dwAddressID As Long, ByVal hCall As Long, ByVal dwSelect As Long, ByRef lpDevice As varString, ByVal lpszDeviceClass As String) As Long
Public Declare Function lineDeallocateCall Lib "Tapi32" (ByVal hCall As Long) As Long