battery

ZEBRA TC75X -> notification battery decommission ?

Hello all,
we have many zebra tc75x.
these devices are more or less three or four years old.

Since today, we have receive some call by user who tell us a new icon appears about battery decommission.

the message is :
this battery is estimated to be past its useful life. Please replace with an alternative battery or contact IT Support.

Ok we can REPLACE battery who can meet problem but the problem is I have this message on more more than 50 devices ...

How to get battery status via Bluetooth (ZQ320, Android)?

I'm trying to get battery status via bluetooth connection for mobile printer ZQ320.
Programming reference says me, that I should use the command "~HB" to receive battery status.
But when I send "~HB" to the printer, printer does not answer anything.
What I'm doing wrong and how to fix it?