Via the Doepfer website:

"The new basic system 3 from Doepfer is a return to Dieter Doepfer's original vision of analogue modular synthesis. Modules can be connected via front panel audio and CV connectors and used in infinite combinations. The Basic System 3 is an easily accessible and well-structured system that can be used by enthusiasts and beginners alike. It can be used as a base for exploring sound synthesis and electronic sounds, or as a supplement to delve deeper into different types of synthesis. For example, it is possible to create 4-part paraphonic patches or create complex sounds using the ring modulator. Percussion and drum sounds can also be created in a variety of ways alongside the classic synth sounds. The system's two filters can also be set to self-resonance to provide additional sound sources. The Waveshaper can be used to modify simple sounds and change their overall timbre. As each user's personal requirements are different, blank panels are installed that can be replaced with modules. This means there is no need to buy a new cabinet.

The following modules are included in the basic system 3:

1x A-108 6/12/24/48dB Low Pass Filter 
2x A-110-1 Standard VCO 
1x A-118 Noise / Random
1x A-121-2 Multimode Filter 
1x A-131 VCA exponential
1x A-132-3 Dual linear/exponential VCA
1x A-137-1 Wave Multiplier I
1x A-138j Inverting/Interrupting Mixer (Janus Mixer)
1x A-138b Mixer logarithm.
1x A-138s Mini Stereo Mixer
1x A-140 ADSR Envelope Generator
1x A-140-2 Dual Mini-ADSR
1x A-147-4 Dual VCLFO
1x A-151 Quad Sequential Switch
1x A-160-2 Clock Divider II
1x A-171-2 VC Slew Processor / Generator
2x A-180-2 Multiples 1
1x A-184-1 Ring Modulator/S+H/T+H/Slew Limiter
5x Blind Panel 4HP"