Check SerialPort Exist Modem ?

Question

In C# 2005, I used the Nokia E63, I want to check SerialPort Exist Modem, While it run does not get run COM port, you see my code

[code]

private void btnGetPort_Click(object sender, EventArgs e)

{

cmbPort.Items.Clear();

foreach (string portName in SerialPort.GetPortNames())

{

try

{

using (SerialPort sp = new SerialPort(portName, 9600))

{

if (!(sp.IsOpen)) sp.Open();

sp.DiscardInBuffer();

sp.DiscardOutBuffer();

sp.Write("AT\r\n");

System.Threading.Thread.Sleep(100);

string response = sp.ReadExisting();

if (response == "OK")

{

cmbPort.Items.Add(portName);

}

}

}

catch (Exception ex)

{

continue;

}

}

}

[/code]