Another Serge classic, the Extended ADSR (ADSR) is (according to the 1983 Serge catalogue):

A complex envelope generator using the four segment envelope normally encountered in keyboard synthesizers. This ADSR, however, is designed with extra features such as voltage control of each section, an initial voltage controllable delay time, switchable slopes and a master voltage control. Each segment may be manually set and voltage controlled, so the module may be used with or without keyboards as a versatile programmable control voltage generator.

In addition to the normal Attack, Decay, Sustain and Release segments, an Initial Delay time is included. This allows multiple envelopes to be initiated from a single trigger or gate, delayed with respect to one another. Ramps for the Attack and Release segments can be switched to either linear or exponential slopes with the three position switch. A master input controls all slope times to allow such effects as decreasing the entire envelope time as the pitch of an associated oscillator increases. This phenomenon is typical of many acoustic instrument envelopes.

The eurorack version uses the original Serge circuitry and is super slim (skiff-friendly). Like in any R*S Serge for eurorack module, the voltage levels of the original design have been preserved - the output voltage is appr. 0 to 5V. This provides maximum authenticity and compatibility with other Serge modules and systems.