Simple example of listening on a port and reading from a socket in PowerShell.

Start-TCPListener.ps1

$listener = [System.Net.Sockets.TcpListener]9999
$listener.Start()
while ($true) {
    $client = $listener.AcceptTcpClient()
    $rEndpoint = $client.client.RemoteEndPoint
    $data = ""
    $stream = $client.GetStream()
    $buffer = New-Object System.Byte[] 1024
    while ($client.Connected -and $stream.DataAvailable -and
            ($i = $stream.Read($buffer, 0, $buffer.Length)) -ne 0) {
        $EncodedText = New-Object System.Text.ASCIIEncoding
        $data += $EncodedText.GetString($buffer, 0, $i)
    }
    Write-Host "$rEndpoint`: $data"
    $stream.Close()
    $client.Close()
}