EDF (European Data Format) is a simple and flexible standard format for exchange and storage of (bio)physical signals. The signals can have any (and different) physical dimensions and sampling frequencies. EDF was published in 1992 in Electroencephalography and Clinical Neurophysiology, 82: 391-393. The specification has not been changed and still has version 0. Designing and programming an EDF import/export unit typically takes a few days. EDF is now widely applied in equipment and software for EEG and PSG recordings.

EDF+ is a more detailed specification of EDF. It is compatible to EDF except that an EDF+ file may contain interrupted recordings. EDF+ also accommodates discontinuous events such as text annotations, stimuli, averaged signals, QRS-parameters and so on. It can store EMG, Evoked Potentials, Electroneurography, ECG and many more types of investigations. Electrode names and annotation texts were standardized. Despite these extras, existing EDF viewers still display the EDF+ signals. Software development is limited mainly to implementing the annotations. EDF+ was published in 2003 in Clinical Neurophysiology 114(9):1755-1761.

Detailed specifications, free software and files, and a list of compatible equipment and software are on http://www.edfplus.info