Eos-Family software can communicate with other devices via OSC (Open Sound Control). OSC is a network protocol that uses either UDP (User Datagram Protcol) or TCP (Transmission Control Protocol).
When using OSC via UDP, the user defines which ports to send and receive messages; for example, Port 8000 for receiving (RX) and Port 8001 for transmitting (TX). The 3rd-party device would have these values reversed - it would receive on Port 8001 and transmit on Port 8000.
When using OSC via TCP, Eos listens for incoming connections on port 3032. TCP is bi-directional, so there is no separate in/out port like with UDP.