Turning the power off then on again allows another test but only one. If the serial port is enabled, the DMC will wait until the printer or computer is ready to receive end of test data. It will not allow another test until the data is sent. If you have a printer check to see that the printer is turned on, paper is loaded, the data cable is connected and the printer is on-line. If a computer is connected check the cable connection to the computer and that the software is running properly. DIP switches 1 & 2 on the bottom of the DMC control the end of test message to the serial port. To disable the end of test message set switches 1 & 2 off.