Connect Bluetooth device via 32feet.Net library

Question

I have a project to connect bluetooth between C# application and my phone, and use AT command through Stream to dial number on my app.

I have seen https://github.com/sidiandi/Sidi.HandsFree but I cannot understand this code.

I try scan and pair, it work well but I cannot connect.

Code:

private void button2_Click(object sender, EventArgs e) {
        BluetoothDeviceInfo[] paired = localClient.DiscoverDevices(255, false, true, false, false);

        foreach (BluetoothDeviceInfo device in devices) {
            bool isPaired = false;

            for (int i = 0; i < paired.Length; i++) {
                if (device.Equals(paired[i])) {
                    isPaired = true;
                    break;
                }
            }

            // if the device is not paired, pair it
            if (!isPaired) {
                // replace DEVICE_PIN here, synchronous method, but fast
                isPaired = BluetoothSecurity.PairRequest(BluetoothAddress.Parse(Addconnect), null);

                if (isPaired) {
                    // now it is paired
                } else {
                    // pairing failed
                }
            }
        }
    }

    private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e) {
        Addconnect = dataGridView1.CurrentCell.Value.ToString();
    }

    private void button3_Click(object sender, EventArgs e) {
        foreach (BluetoothDeviceInfo device in devices) {
            if (device.DeviceAddress.ToString() == Addconnect) {
                try {
                    localClient.SetPin(null);
                    localClient.BeginConnect(device.DeviceAddress, BluetoothService.SerialPort, new AsyncCallback(Connect), device);
                }
                catch {                       
                }                  
            }
        }
    }