Вот пошерстил еще по инету, нашел у буржуев

1. confirmed AEM EMS is setup properly.
2. connected PC directly to AEM EMS and monitored serial traffic with TTY application - confirmed AEM EMS is outputing telemetry.
3. connected AEM to RT serial adaptor, and configured as "PC monitor only" using RT supplied null modem cable between serial adaptor and PC. Checked Monitor Lite and TTY application, and confirmed that no telemetry is reaching the PC.

I have also swapped null modem cables with two others to confirm that it is not a null model problem. The issue appears to be with the RT serial adaptor. Can you please confirm?
Here are screen shots to verify:

AEM telemetry settings:



Lite Monitor - this was with the "DL1 and PC Monitor" configuration - shows communication with DL1 is good, but no serial output:



TTY output - PC & AEM EMS linked directly:



no TTY output - configured as "PC monitor only" with serial data out to powered terminator and serial data in connected to PC with supplied RT null modem cable: