The Digital Sleep Recorder has three module slices. The top one is the "Sleep" slice, and receives inputs for the sleep signals (EEG, EOG, and EMG) from the E-net worn by the crewmember during sleep. The middle one is the "Borg Harness" slice, receiving inputs from the Borg Harness, a cable which houses connections for ECG, Respitrace, pulse oximetry, a nasal airflow thermistor, a microphone and light sensor, and an event marker. The bottom slice is the "Analog" slice, which outputs signals to the ALFE hardware during awake data sessions.