We have a ZT230 connected to USB port and have been using ZSDK_API.jar to access Zebra printer.
It works, but it takes almost 30s to que status response before printing,
To discover the VID/PID of connected USB printer, we use:
"printer" = java -jar ZSDK_API.jar discover -u
Then, to get printer status:
java -jar ZSDK_API.jar status -p "printer"
This command takes 30s to return.