Can anyone help me understand the "Unknown message AT: 100" error. It pops up everytime I open the Elk node server.

Thanks,

Andrew

It is benign, you can ignore. I created a issue: https://github.com/UniversalDevicesInc-PG3/udi-poly-ELK/issues/120

Got it. I'm guessing here...but is this the heartbeat signal sent to the central station?

Yes, that's what is detailed in the issue link

Need to ignore this, AT is the command code for an Alarm Reporting / Ethernet Test Command. It is a system keepalive or signaling message—frequently sent when the ELK panel or its M1XEP ethernet module runs an internal network/IP pathway test. https://www.scribd.com/document/508689172/Elk-m1-Rs232-Protocol-Ver-1-84