Access the main menu on the pneumotachometer's operating screen. Choose "Calibrate" in the main menu. The next choice can vary depending on the manufacturer but should display something like "Calibrate Pneumotachometer" if it doesn't take you directly to a calibration screen.
Attach the calibration syringe to the pneumotachometer. With most models, this is done on the occlusion block.
Choose "Run" or "Start." Manipulate the syringe as directed, pushing or pulling. Repeat this process several times, saving the data with each run and incorporating rates of gas flow from zero to 2000 milliliters per second. A message appears on the screen when the device is sufficiently calibrated.