Function Send-TCPMessage { 
    Param ( 
            [Parameter(Mandatory=$true, Position=0)]
            [ValidateNotNullOrEmpty()] 
            [string] 
            $EndPoint
        , 
            [Parameter(Mandatory=$true, Position=1)]
            [int]
            $Port
        , 
            [Parameter(Mandatory=$true, Position=2)]
            [string]
            $Message
    ) 
    Process {
        # Setup connection 
        $IP = [System.Net.Dns]::GetHostAddresses($EndPoint) 
        $Address = [System.Net.IPAddress]::Parse($IP) 
        $Socket = New-Object System.Net.Sockets.TCPClient($Address,$Port) 
    
        # Setup stream wrtier 
        $Stream = $Socket.GetStream() 
        $Writer = New-Object System.IO.StreamWriter($Stream)

        # Write message to stream
        $Message | % {
            $Writer.WriteLine($_)
            $Writer.Flush()
        }
    
        # Close connection and stream
        $Stream.Close()
        $Socket.Close()
    }
}

Send a message with:

Send-TCPMessage -Port 29800 -Endpoint 192.168.0.1 -message "My first TCP message !"

Note: TCP messages may be blocked by your software firewall or any external facing firewalls you are trying to go through. Ensure that the TCP port you set in the above command is open and that you are have setup the listener on the same port.