4.主要方法与事件代码
'设置可用串口
Private Sub Form_Load()
On Error GoTo error_open
For i = 1 To 4
MSComm1.CommPort = i
MSComm1.PortOpen = True
'设置可用的第一个串口
On Error GoTo 0
Exit Sub
error_resume:
Next
error_open:
Resume error_resume
End Sub
Private Sub DialButton_Click()
Dim Number$, Temp$
Number$ = Trim$(Txttel.Text)
If Number$ = “" Then
MsgBox “请输入电话号码"
Txttel.SetFocus
Exit Sub
End If
DialButton.Enabled = False
QuitButton.Enabled = False
DialString$ =“ATDT”+ Number$ + “;” + vbCr
'清除接收缓冲区
MSComm1.InBufferCount =0
'拨电话号码
MSComm1.Output = DialString$
Lblmessage.Caption = “正在拨号码 -”+Number$
DialButton.Enabled = True
QuitButton.Enabled = True
End Sub
Private Sub MSComm1_OnComm()
Select Case MSComm1.CommEvent
Case comEvReceive
'读取串口数据
COMBUF=COMBUF + MSComm1.Input
lc = InStr(1, COMBUF, “OK”)
If lc = 0 Then Exit Sub
'Modem已正常拨号,返回OK
Lblmessage.Caption = “请您摘下电话机,
准备通话”
Case comEvSend
End Select
End Sub
Private Sub CancelButton_Click()
'断开与调制解调器的连接
MSComm1.Output = “ATH” + vbCr
End Sub
实例2:实现来电显示
在一些实际应用中,需要显示并保存来电号码,并根据电话号码显示相应资料,比如小区物业管理和110报警等系统。
实现步骤:
1.创建窗体
●添加一个MSComm控件,用来建立与串口的连接;
●添加4个Option控件,用来确定使用的串口号;
●添加4个Label控件,用来显示来电号码及日期时间;
●添加一个ProgressBar控件,用来显示电话振铃次数;
●为方便调试程序,添加一个Text控件Text 5,用来显示Modem传来的所有信息。窗体见图2。
3.程序功能
程序首先初始化Modem,然后等待来电。当有来电时,MSComm产生OnComm事件。Modem送出的信息格式为“DATE = 月日回车换行TIME = 时分回车换行NMBR = 电话号码回车换行”。在OnComm事件处理程序中对读入信息进行截取,截取电话号码后,以该电话号码为关键字,查询并显示数据库中有关信息。
4.主要方法与事件代码
'通用声明部分
Const DEBFLG = 1
Public COMX, BEEPNO, HANGUP,PNLOC As Integer
Public COMBUF, COMLIN As String
Private Sub Form_Load()
'检测串行口
Dim I, C As Integer
COMX = 0
COMBUF = “”
COMLIN = “”
BEEPNO = 0
HANGUP = 0
'正常运行程序,关闭右侧Text5
If DEBFLG= 0 Then
Form1.Width = Form1.Width - Text5.Width
Text5.Enabled = False
Text5.Visible = False
End If
On Error GoTo ERROR_FORM_LOAD
'检测可用串口
For C = 1 To 4
If MSComm1.PortOpen Then MSComm1.PortOpen = False
MSComm1.CommPort = C
If Not MSComm1.PortOpen Then
MSComm1.PortOpen = True
If MSComm1.PortOpen Then MSComm1.PortOpen = False
If COMX = 0 Then COMX = C
FORM_LOAD_1:
Next C
If COMX = 0 Then End
On Error GoTo 0
Option1(COMX - 1).Value = True
Exit Sub
ERROR_FORM_LOAD:
Option1(C - 1).Enabled = False
Resume FORM_LOAD_1
End Sub
'选择串行口
Private Sub Option1_Click(Index As Integer)
COMX = Index + 1
Call INIT_MODEM
End Sub
'初试化Modem
Private Sub INIT_MODEM()
If MSComm1.PortOpen Then MSComm1.PortOpen = False
MSComm1.CommPort = COMX
If Not MSComm1.PortOpen Then MSComm1.
PortOpen = True
MSComm1.Output = “AT#CID=1” + vbCr
'检查Modem命令是否完成
Call CHK_MODEM
MSComm1.Output = “ATS0=0” + vbCr
End Sub
'检查Modem命令是否完成
Private Sub CHK_MODEM()
Dim T As Single
Dim L As Integer
T = Timer
Do
COMBUF = COMBUF + MSComm1.Input
L = InStr(1, COMBUF,“OK”)
Loop Until L <> 0 Or Timer - T > 1
If L = 0 Then
Line1.Visible = True
Line2.Visible = True
Form1.Show
MsgBox “MODEM未联机”,vbOKOnly+vbCritical,“测试MODEM”
Else
Line1.Visible = False
Line2.Visible = False
End If
End Sub
'串行口接收事件处理
Private Sub MSComm1_OnComm()
Dim CH, ST