高手求助 MScomm问题

小弟初学VB 用MScomm串口通信  将串口2，3针短接测试所写代码 form上的Text没有发送的字符求助！

Option Explicit

Private Sub Form_load()
MSComm1.CommPort = 1
MSComm1.Settings = "9600,o,8,1"
MSComm1.InBufferCount = 0
MSComm1.OutBufferCount = 0
MSComm1.PortOpen = True
End Sub

Private Sub Command1_Click()
    MSComm1.Output = "aaa"

End Sub

Private Sub MSComm1_OnComm() '接收
Select Case MSComm1.CommEvent
    Case comEvReceive
         Dim buffer As Variant
         MSComm1.InputLen = 0
         MSComm1.InputMode = comInputModeText
         buffer = MSComm1.Input
         Text1.Text = buffer
    Case Else
End Select
End Sub

Private Sub Form_Unload(Cancel As Integer)
  MSComm1.PortOpen = False
End Sub --------------------编程问答-------------------- 已解决没设置RThreshold --------------------编程问答-------------------- 呵呵,恭喜 --------------------编程问答-------------------- 祝贺LZ自己找到问题!

--------------------编程问答-------------------- 恭喜！！！ --------------------编程问答-------------------- 恭喜！！！ --------------------编程问答-------------------- 楼主还真牛呢 --------------------编程问答-------------------- JF来的

补充：VB ,  控件