SerialPort read/write using same opened port

See more:

serial-port

I am trying to use SerialPort object to listen for incoming data and send outgoing data.

Doing each other separately, it is working well - I can send or receive with no issues. The problem happens when I want to make this port available for both operations.

What I do is this (In a dedicated thread):

private void SerialCommunicationsListen(SerialPort serialPort)
{
while (true)
{
string val = serialPort.ReadLine();
// do some code with val
}
}

This is the listener. 2nd thing I'm doing is this for sending data out:

public void SendMessage(SerialPort port, string message)
{
port.Write(message);
}

Both are using the same SerialPort object. The thing is that if I call "SendMessage" when the listener is up, the listener receives the data instead of the device, and if it is down, the device is the one receiving it.

What am I doing wrong here? I want to do both transmit and receive from the device on the same port.