Module A-141-2 is the successor of the obsolete former VCADSR module A-141. Compared to the A-141 a lot of improvements and expansions have been added: 
common control voltage input for all time parameters (A/D/R), range switch for three different time ranges, inverted ADSR output, additional output with voltage controlled level (i.e. built in output VCA), digital outputs for End of Attack (EOA) and End of Release (EOR), EOR is e.g. required for the VCLFO mode. 

Module A-141-2 (VCADSR) is the voltage controlled version on an ADSR type envelope generator - a bit like the the voltage controlled version of the A-140. Whenever a gate signal is sensed at the VCADSR's gate input, an adjustable sequence of voltages is triggered - the envelope. You can then use these envelopes to modulate a VCO, VCF or VCA, or to control any other voltage controlled parameter of an A-100 module, e.g. Phasing A-125, Frequency-Shifting A-126, BBD-Delay A-188-1/A-188-2 or Waveshaping A-116/A-137. 

The shape of the envelope is governed by four parameters: Attack, Decay, Sustain and Release. On the A-141, these parameters can be controlled by hand, or by voltage control, via the dedicated CV inputs (each with an attenuator). 
The A-141 VCADSR also has a retrigger facility: while the gate is open, a trigger pulse received at the retrigger socket will re-start the envelope from the beginning of its attack phase. 

The time range for A, D and R is about 3 ms ... 20 s. The module can be modified upon request (changing a capacitor) for another time range, e.g. 300us... 2s.

technical details

Width: 14HP 

Connections: 
CV input A 
CV input D 
CV input S 
CV input R 
EOA output 
EOA output 
Inv. output 
Level CV output 
Common CV input 
Gate input 
Retrigger input 
Fixed out 
Var. output