Comparison of k83 Decoders and compatible devices

Table of Contents

Preface - Turnout Decoders

With turnout decoders here I differentiate between so-called "four-turnout decoders" and "single turnout decoders". The four-tournout ones are the boxed or bare circuit decoders mounted underneath the layout, where up to four double-solenoid turnouts are connected to. The single turnout ones are bare circuit decoders to be mounted directly into the turnout. This makes a turnout with built-in decoder so that no more wiring is necessary, which is most convenient for temporary layouts.

four-turnout Decoders

type number no of turnouts processor programming comment
märklin k83 6083 4 145027 DIP, inside box the märklin reference. schematic.
Viessmann 5211,
kit 5291
4 145027 DIP, accessible short circuit protection, separate power supply possible, 2 A per output
4 Z80 microcontroller program button ULN2003 driver ICs (NPN), inverted output voltages, 1 A per outputs 1,2,3; 0.5 A per output 4
kit S-DEC-4-MM-B
4 Z80 microcontroller program button ULN2803 driver ICs(NPN), inverted output voltages, separate power supply possible, digital input and power input separated via optocoupler, short circuit protection, 1 A per output
tams elektronik WD-1 4 145027 4 jumpers discrete NPN drivers, inverted output voltages, 1.5 A per output
Carsten Meyer WD4 do-it-yourself WD4 4 145027 DIP separate power supply possible, limited output protection

inverted voltage - usually, the internal operating voltage is taken from the negative supply pulses (because in the digital signal the voltage is longer negative than positive). The yellow output is the internal negative voltage, the blue outputs get the internal positive voltage switched by PNP transistors. The internal positive voltage level is equal to the brown (typically called ground) input connection. Decoders with inverted voltage, however, have opposite voltage levels at their output. Whatever version it is, it should always be possible to wire push buttons (like signal box 7072, between blue turnout wire and brown supply wire) for manual operation in parallel to the decoder.

The Viessmann decoder offers best compatibility with the original k83, as well as the WD4. the Littfinski S-DEC-4-MM is unique as it has electrically insulated separate power supply. The QS-DEC-II and WD-1 are low price alternatives.

The Viessmann decoder and early versions of Märklin's k83 have individual common power transistors for each output, which are easy to replace if damaged. New k83 have special SMD transistors making their damage difficult to repair.

single turnout Decoders

type number no of turnouts processor programming comment
märklin k73 6073 1 145027 solder bridge tailored to M-track turnouts. Out of production.
märklin ??? ??? 1 145027 solder bridge a decoder like the k73. Was factory built-in into "digital" M-track turnouts. Only very restricted number of addresses configurable!
märklin 74460 74460 1 145027 DIP tailored to C-track turnouts.
Viessmann 5231 1 microcontroller 6021 programmable tailored to C-track turnouts. Märklin Motorola and DCC multi-protocol. separate power supply possible.
Dr. König do-it-yourself 1 145027 solder bridge Dr. König's DIY decoders, equivalent to märklin's decoders. He offers versions for M- and C-turnouts. A variant is also available for three-way turnouts. König's speciality is the possibility to remotely switch the lantern light.

A user has reported that from time to time his Viessmann's multiprotocol decoders may unwantedly reprogram themselves. I cannot prove or confirm this.

^ back to main document ^

last update: 2004-02-21; webmaster(at)