Please fix the TCP Output Node.
The TCP Output requires special consideration if you need to append the sent string with control characters. You apparently need a function node in your flow to fix the apparent problem. If it is not going to be addressed, then it needs to have a reference in the "Info Tab". This has been an known issue since at least 11/15/2015.
"Nick O'Leary, 11/15/15
The inject node does handle escape sequences like \n - it treats them as literal strings.
For now, use a Function node after your Inject node to append the newline:
msg.payload = msg.payload + '\n';