Unpause While Receiving Data (ZT230)

I have a ZT230 printer.  I send it several labels (50-100) to print, each as a separate job, via the print driver.  The driver is set up to pause after each job.

I need to programmatically unpause the printer asynchronously, so I'm sending a SGD command to unpause directly over ethernet to the printer.  This works fine during testing, but is failing when the printer has been sent a lot of labels.

One thing of note is that when it fails, the "data" LED on the front of the printer is blinking - I assume it's because it doesn't have enough memory to hold all of the labels and the driver is trying to drip feed them to it?  I need to be able to unpause it while in this state so it can continue processing the labels in the queue.

1. Is my assumption correct that it's failing to unpause because it's "busy", as indicated by the flashing data LED?

2. How can I get it to unpause while in this state?  Do I need to control the input stream to decrease the labels going in (that would be painful)?