Modulair (Eurorack) system.  Model 3000. 

Brief description of most S3000 modules. A 3-unit AKA rack fits 5 regular-width (Eurorack) , 10 half-width or a combination of modules.

They are powered by regulated +15.0, 0, and -15.0 Volt supply. The modules have no rear cover, so they need a protective case or rack.
The module dimensions are similar, but not identical to Doepfer and Paia modules.

Synton starts with the common modules ( VCO, VCF, VCA EGR LFO).  Later modules were created from names of famous instruments. like DMX and PPG.

3003 KBI
Keyboard interface

3004 4ATT
Quad Attenuator

3005 EGR
Discrete ADSR with manual trigger button and LED.

Multiple, 4 cv out with potmeters

3010 VC-EGR
Curtis-based ADSR with four CV-inputs. Uses CEM3310

3015 MXA
3-1 mixer with unity-gain input.

3016 MXI
Half-size mixer with one unity-gain input and one variable invertible input. For adding vibrato to keyboard CV and other simple tasks.

3017 VCF
State-variable 12 dB filter. One output is Band pass, the other has a control for low-notch-high pass. Uses CA3280

3021 VCO
Uses a Curtis chip. Triangle, saw and variable pulse outputs, hard sync and PWM inputs. Uses CEM3340

3022 DIV
Half-size binary pulse-divider with 2 / 4 / 8 outputs. Useful for making sub-octaves. Logic 0/10 volt output, so you may need to shift and attenuate.

3023 LFO
Half-size LFO with reset-input. Variable waveform pulse and triangle/sawtooth outputs.

Line output amp

Mic/line input amp

3037 PPG
trigger sequencer/ voltage controlled puls generator

3044 DMX
4 channel de-multiplexer

3209 VCA
Dual VCA with positive gain-offset controls. This can be used for feeding a sound to the output without an envelope while testing or tuning. Uses CA3280

3211 PRM/NRG
Ring modulator, white/pink noise with level control, VLF noise with level control. Uses CA3080

3216 DIV
Dual divider

3218 INV / SLR
Dual inverter with offset controls (also used as variable voltage source) and slew limiter with rise and fall controls. This can be used as simple AR envelope.

3223 2LFO
Dual LFO with VC speed. Square and triangle outputs. Uses Ca3080

3224 High-low pass 24 dB VCF
Uses two Curtis chips, one for high pass, the other low pass. Both are 4-pole 24 dB/octave VCF’s. There is a CV input to control low pass resonance. Uses CEM3320

3233 S&H / LFO
Sample and hold with clock and LFO.

3235 ENV / CPR
Envelope follower and comparator with reference level control.

3242 MMX
Dual two input analog switch

KBM 35 Keyboard
44-key monophonic keyboard with touch pad rather than wheels. Scale control.

External power supply,  Use 78GU and 79GU regulators