Earth Networks is deploying cavity ringdown spectrometers at 100 towers to measure CO2 and CH4. We describe the greenhouse gas instrumentation (pumps, tubing, calibration gases, nafion, filters) and supporting instrumentation (anemometer, thermometer, hygrometer) each station includes. We also describe our calibration method and our choice of which data to achive. We present examples with real data to illustrate the role each part of the system plays, to illustrate how we calibrate, and to illustrate what we store.