First Alert ACTION T-1000 - Manual (Page 53)

Beeper Error Warnings
When the printer’s beeper sounds, it usually indicates that the printer is
out of paper. If the printer beeps and stops printing when it is not out of
paper, turn the printer off and check to see that the paper is loaded
correctly. If the paper is loaded correctly, turn the printer back on and
try to print again. If the printer beeps and does not print again, take it to
a qualified service person.
4-4 Troubleshooting and Maintenance