EtherCAT frames in UDP datagrams (ETG.1000.4, 5.3.2), sent to port 0x88A4 (34980) of a host unless another is given, and answered from there.
EtherCAT.MainDevice.start_link(udp: {{10, 0, 0, 9}, 34980})A segment answers over UDP only behind something that takes the datagrams to it, so this is mostly
for tests and simulators. Options of open/1:
host:, required, an address as a tuple or a nameport:(34980)