Lets start with some sample data:
echo "Message sent to Logit.io using TCP" >> tmp.log
Sending the log to logstash with openssl over TLS
cat tmp.log | openssl s_client -connect your-logstash-host:your-port < tmp.log
Sending the log to logstash with netcat without TLS (This is not recommened for production)
cat tmp.log | nc your-logstash-host your-port
Take a look in your kibana for your message.