Send Command to GPS

I need some help for testing a command. FMB920 Teltonika has a Digital Output. On the I/O elements manual i see this entry.

Nr.	Property ID in AVL packet	Property Name	Bytes	Type	       Min	Max	Multiplier	Units	Description	HW support	 
20	            179	                        Digital Output 1	   1	    Unsigned	 0	 1	   -	           -	         Logic: 0/1	FMB920 

I understand that i have to use AVL ID and send 0 or 1 to disable/enable the output with a custom command.
I can't find anywhere in forum how will this command will look like. I checked GPS manual and says only about sms.
Can this be done and can you point me to where I can look to make it work?
Thank you.

https://github.com/tananaev/traccar/issues/1948
According to this teltonika commands are implemented. But when i go to devices>commands i see nothing.
Also i made custom command and it's not showing there.
Should i try the debug suggestion you are writing?

Screenshot please.

https://imgur.com/a/fgeEU

You will notice device is offline when i took screenshot.
Same thing is when it's online. I see nothing on commands just new>custom command.
Should it have any ready commands there?

It might mean that you linked unsupported command to the device.

I tried almost all ready commands, and the only one i see when i press the device commands is the custom one.
So i guess i have to use a custom command with the proper format in order to get Digital Output to 0 or 1.
But according to this https://docs.google.com/a/traccar.org/spreadsheets/d/1BTbIQ9nlkwqDO1s9AnoighdxyiwCSCCVVEBdi0dOjTU (id 179), what i want is compatible.
Correct me if i am wrong. Should this command be implemented in commands as a choice or when you say compatible you mean that you can do it with custom command and i have to find how will the format be?

Traccar only supports custom command for Teltonika.

OK, so i have to check with teltonika and ask them how should the command be. GPS manual says nothing about gprs commands. Only thing i have found so far is about codec_12 support.
If you have any suggestion for this command let me know.

GPRS commands mostly the same as SMS, you can try setdigout

I tried this and i get "unknown command or invalid format" as answer after i decoded with hex.
Still trying...No answer from Teltonika support also...

I have fmb920, sent setdigout 0 and got answer DOUT1:0

Strange first time i tried it, it didn't work...Now it did. Thank you.

@psekinho,
did you send the GPRS command (in my case to cut of engine) through Web API or Traccar's portal?