Does the Zebra QLn220 printer have a “Flush” Command?

Question

The ZebraQLn220 has many settings that can be programmatically updated via commands sent it, such as:

! U1 setvar "media.sense_mode" "bar"

However, sometimes it takes several attempts before that change is "seen"/accepted/applied by the printer. For instance, I have sent the

! U1 setvar "power.dtr_power_off" "on" 

command several times before this one:

! U1 getvar "power.dtr_power_off"

...will finally respond back with "on" (giving me "off" instead the first several times).

So: Is there a command that can be sent to the QLn220 that tells it to "flush" or "write all changes" or "save changes" or "I really mean it this time" or some such?

UPDATE

I don't know what firmware is new enough, but this is what the printer tells me about itself as far as "appl" settings go:

appl.date : 2/19/2014 
appl.name : V68.19.7Z 
appl.version : 6819 
appl.bootblock : 2.5.9 
appl.link_os_version : 2.0

Answer 1

If you are using later firmware you can use JSON to format the commands. In this method the commands will respond immediately with the configured values.

{}{"media.sense_mode":"bar"}

would respond with:

{"media.sense_mode":"bar"}

You can also put multiple requests in one:

{}{"media.sense_mode":"bar",

"power.dtr_power_off":"on"

}

The following knowlege base article has more info - https://km.zebra.com/kb/index?page=content&id=SO8638&actp=RSS