'Hi, habilitaste el handshake del puerto com?
'Esta rutina esta hecha en Visual Basic 2008 Express
'
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.SerialPort1.Open()
Me.SerialPort1.Handshake = IO.Ports.Handshake.RequestToSend
End Sub
Private Sub Form1_Close(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.SerialPort1.Close()
End Sub
Private Sub Button1_Click1(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
Me.SerialPort1.DtrEnable = True
Me.SerialPort1.RtsEnable = True
End Sub
Private Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click
Me.SerialPort1.DtrEnable = False
Me.SerialPort1.RtsEnable = False
End Sub
End Class