Why only one MIDI port?

[ChSys]

Why only one MIDI port on the Essentials 61?  I am finding USB to be undependable and would prefer to use MIDI instead with Logic Mainstage.  However, don't I need both MIDI in and MIDI out? 
What is the purpose of only one MIDI jack?

[MajorFubar]

It's a midi controller, it cannot receive midi information, only transmit it, consequently it only has a midi out and not a midi in.
What issues are you having with USB? USB is by far the better connection and facilitates true integration between the controller and analog lab. Midi DIN sockets are so 1983 :-)

[ChSys]

I get nervous using Mainstage in live situations. Like just now. I set everything up, starting Mainstage after all connections are made. MIDI is responding in the top center window. Keys respond on the virtual keyboard on my screen. Yet I get no sound. Panic! If I'm lucky, I can quit Mainstage, and try again, and this time it will work.  Mainstage Users Facebook page advised that MIDI pin ports are more dependable and what the pros use.