POWER ON/OFF: The ON button is marked in green (number 11, Figure A1) and the OFF button is number 12 above. Press the ON key once. The upper screen lights up and the pacers initiates a self-test. Once a successful self-test is completed the following occurs: A sufficiently charged battery will allow the device to begin sensing and pacing in both the atrium and ventricle at the following nominal parameter values. Press the “OFF” button twice within 5 seconds. After the first press, a message appears in the lower screen telling the user to press OFF a second time to turn the device off.