twin-center_info_en - LDT

Littfinski DatenTechnik (LDT) 

Kleiner Ring 9 • D-25492 Heist/Germany • Phone: 0049 4122 / 977 381 • Fax: 0049 4122 / 977 382 

Sample Connections: 

TWIN-CENTER from Fleischmann 

The TWIN-CENTER transmits the Fleischmann owned FMZ-Format as well as the standardized 

DCC-Format to the Lok- or accessory-decoder. This enables the control-unit to respond to LDT- 

Decoders for the DCC-format. 

The TWIN-CENTER provides the s88-feedback bus for feedback of events from the tracks. 

The LDT-Feedback Modules RM-DEC-88 and RM-DEC-88-Opto (both for quick-action 

switches) and RM-GB-8 (for track occupancy reports) can communicate with the TWIN- 

CENTER without any problems. 

On the next pages you will find some recommendations and sample connections of the TWIN- 

CENTER connected to LDT components. 

1. Supply tracks with digital current: 

The rail connectors within a layout provide a considerable high transition resistance for the digital 

current. At a distance of 4 meters from the feeding connection the digital current can be eventually 

reduced to such a low value that the Lokdecoder receives no useable information anymore. 

Vom Modellbahntrafo 

From transformer 

schwarz 

black 

gelb 

yellow 

violett 

violet 

violett/weiß 

violet/white 

FLEISCHMANN 

TWIN-CENTER 

Via a separate main ring with several supply connections the digital-current supply to the rails 

will be optimized. 

Littfinski DatenTechnik (LDT) Address Phone Banking connection 

Internet / e-mail Kleiner Ring 9 0049 4122 / 977 381 Kreissparkasse Suedholstein 

http://www.ldt-infocenter.com D-25492 Heist/Germany Fax (bank code 230 510 30) 

info@ldt-infocenter.com 0049 4122 / 977 382 Account-No. 3 99 43 57 

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Therefore you should plan a main-ring-supply for the digital current. The wires should have 1mm² 

at a minimum. About every 2 meters one supply connection to the rail should be provided. 

2. Using the LDT Accessory Decoder: 

LDT offers various accessory decoder for the DCC-Data format. Those are suitable for the use 

on TWIN-CENTER of Fleischmann. 

Under the expression S-DEC-4-DC we offer a Turnout-Decoder for the switching of single- and 

twin-coil magnetic accessories such as turnouts, signals or un-coupling tracks. 

You can purchase by us the Switch-Decoder (SA-DEC-4-DC) for digital switching illuminations 

on and off or switching track sections current-free e.g. at a hidden siding or in front of “red” 

signals. 

G 3 R 4 R 

Black 

K 

G S1 red brown 

KL1 

Red 

J 

violett 

violet 

violett/weiß 

violet/white 

Digital-Profi werden! 

Magnetartikel-Decoder 

S-DEC-4-DC 

Für 4 Doppelspulenantriebe für NMRA DCC 

Digitalsysteme. Schaltstrom: 1 Ampere pro 

Ausgang. 

Littfinski DatenTechnik 

D-25492 Heist 

Multi-Digital 

www.ldt-infocenter.com 



schwarz 

black 

gelb 

yellow 

KL2 

~ ~ 

14 .. 18V 

4fach Weichendecoder 

Accessory Decoder 

S-DEC-4 

Rev. 2.1 


G 1 R 

G 2 R 

FLEISCHMANN 

TWIN-CENTER 

Turnout-Decoder S-DEC-4-DC for switching turnouts or signals with twin-coil drives. 





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Further we supply a decoder (M-DEC-DC) for motorized turnout drives within our program. If 

you intend a digital and exemplary switching of light signals on your layout you can use our Light 

Signal-Decoder LS-DEC. 

Further detailed information to the different decoder and their operation within the layout can be 

found on our LDT Web-Site (www.ldt-infocenter.com) at the section “Downloads”. There are all 

Operation-Instructions and further information such as Sample-Connections available. 

On the connection plan (last page) we extended the layout by a Turnout-Decoder S-DEC-4-DC 

which can digital switch both turnouts. 

To assure that the current required for switching the turnouts will not charge the digital current 

circuit, the decoder S-DEC-4-DC will get the supply from an external AC-output of a 

transformer (as the TWIN-CENTER as well). This saves expensive digital current. All our 

decoder offer this convenient possibility. 

As shown at the connection plan, the digital voltage required for the decoder will be directly 

supplied from the TWIN-CENTER. For this purpose you should assemble a second main ring 

supply below your layout for the supply of all accessory decoder with digital information from the 

TWIN-CENTER. As the digital information at the rails can be considerable disturbed by travelling 

vehicles the use of this information by a direct connection to the rail should be avoided. 

2.1 Recommendation for operating LDT-Decoder on TWIN-CENTER: 

2.1.1. Registration of DCC Decoder on TWIN-CENTER 

As per factory adjustment the TWIN-CENTER transmit FMZ-data to the decoder. To operate the 

LDT-Decoder the respective addresses have to be changed to DCC. 

This operation is described within the TWIN-CENTER operating manual at paragraph 8.1 

turnout/signals registered at the TWIN-CENTER on page 39. 

Four statements have to be adjusted for each address: 

1. The so-called Virtual Address (from 1 to 2048). This complies e.g. to the number of a turnout. 

2. The Decoder Address or the decoder number. There are values of 1 up to 512 adjustable. 

3. At the decoder output values between 1 to 4 can be adjusted (as all LDT-Decoder contain four 

outputs). 

4. The Data Format. It has to be set to D for DCC, if the LDT-Decoder shall take over the 

switch events. 





3



As the required adjustments at the TWIN-CENTER will cause probably at first some problems, we 

have created a table for your assistance including all details for the first 512 virtual addresses. 

Please load the file twin-center_adressierungstabelle1.zip to your PC. 

2.1.2. Programming the decoder address 

During the operation at the TWIN-CENTER it can happen that after actuating the programming 

key the decoder will switch the turnout at output 1 immediately into a fast sequence such as it 

would confirm the programming of an address. In this case the address repetition storage of the 

TWIN-CENTER contains by error data on which the decoder is already reacting. 

Proceed now as follows: 

1. Program the decoder immediately after switching-on the digital central unit, before any loc is 

travelling. 

2. Proceed with a RESET of the digital central unit. All stored data will be preserved, only the 

address repetition storage will be deleted. On the TWIN-CENTER you have to activate at 

switched-on status the keys GO and STOP together until “reset” will be shown at the display. 

2.1.3. Adjusting the switching times 

The TWIN-CENTER output is not a clear DCC-data format but a mixture of FMZ and DCC 

format. 

LDT-Decoder are optimal tuned to this data format. But will the decoder not switch always 

reliable it is possible to adapt the TWIN-CENTER to the requirement. 

At the paragraph 8.5 Adjustment of switching time (page 42 of the TWIN-CENTER Operating 

Manual) this procedure is explained in detail. The factory adjustment has been set for the minimal 

and maximal switching time of 50ms. 

To solve the above described problem please extend the switching time up to 250ms. 





4

8 

7 

6 

5 

4 

3 

2 

1 



3. Operation of LDT Feedback Modules on the s88-feedback bus: 

The TWIN-CENTER is equipped with a s88-feedback bus and enables therefore the possibility to 

operate the LDT-Feedback Modules with this system 

At the s88-feedback bus all feedback modules are connected behind each other and build therefore 

a feedback line. 

Different feedback modules (even from different manufacturer) can be combined within the 

feedback line. 

The first feedback module shall be connected directly to the TWIN-CENTER (LDT-Feedback 

Modules are equipped with an original plug for the TWIN-CENTER), all further modules shall 

follow and build together a feedback line. 

2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16 

1.10 1.12 1.14 1.16 1.2 1.4 1.6 1.8 

1.9 1.11 1.13 1.15 1.1 1.3 1.5 1.7 

8 7 6 5 IN2 4 3 2 1 IN1 

8 7 6 5 IN2 4 3 2 1 IN1 

10 

9 

11 

16 

15 

14 

13 

12 

3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 

Digital-Profi werden! 

Rückmeldemodul 

RM-DEC-88 Opto 

16 galvanisch getrennte Rückmeldeeingänge 

für den s88-Rückmeldebus. 

Multi-Digital 


D-25482 Appen 

www.ldt-infocenter.com 

IN 

ST2 

pink 

grey 

yellow 

green 

brown 

white 

RM-GB-8 

Rev. 2.1 


ST2 

pink 

grey 

yellow 


brown 

white 

RM-GB-8 

Rev. 2.1 


decoder s 88 

8 7 6 5 4 3 2 1 

märklin 

digital 

Rueckmeldedecoder RM-DEC-88 

16-channel feedback modul 

Rev. 2.0 

Peter Littfinski DatenTechnik 

rosa 

OUT 

ST1 

weiss 

braun 

gruen 

gelb 

grau 

IN 

ST2 

rosa 

grau 

gelb 


braun 

weiss 

ST1 

8fach Rueckmeldemodul 

mit Gleisbesetztmeldern 

Octal feedback modul 

with occupancy detectors 

rosa 

grau 

gelb 


braun 

weiss 

ST1 





9 10 11 12 13 14 15 16 

OUT IN OUT OUT 

3.9 3.10 3.12 3.14 3.16 

3.11 3.13 3.15 

S88- feedback bus 

S88- Rückmeldebus 

FLEISCHMANN 

TWIN-CENTER 

LDT-Feedback Module (RM-DEC-88-Opto for quick action switches and RM-GB-8 with integrated track 

occupancy reporting) and a Märklin s88-module at the s88-feedback bus of the TWIN-CENTER. 

At the sample connection is at first the Feedback Module RM-DEC-88-Opto with 16 inputs for 

quick action switches (reed contacts etc.) directly connected to the TWIN-CENTER as the first 

module. 

It follows by two RM-GB-8 with 8 track occupancy detectors each and a s88-standard module 

from Märklin. 





5



Further information to our feedback modules for quick action switches and the useable rail 

contacts can be found within the file “rmdec_info_engl”. Those can be loaded to your PC from 

our Web-Site (www.ldt-infocenter.com) at the area “Downloads” or red and printed with the 

Acrobat Reader. 

If you require a transmittance of track occupancy reports from a 2-conductor rail system to the 

TWIN-CENTER (and eventually further report to the model railway software at the PC), our 

Feedback Module with integrated track occupancy detector RM-GB-8 will be an excellent 

solution. The monitored track sections get the digital current supply via the feedback module. Has 

been a current consumer located at the monitored track section this will be reported to he TWIN- 

CENTER via the s88-feedback bus. 

Ç 

Ç 

Ç 

Ç 

8 7 6 5 IN2 4 3 2 1 IN1 



schwarz 

black 

gelb 

yellow 

violett 

violet 

violett/weiß 

violet/white 

ST2 

pink 

grey 

yellow 


brown 

white 

rosa 

grau 

ST1 

gelb 


braun 

weiss 

RM-GB-8 

Rev. 2.1 






RM-GB-8 

FLEISCHMANN 

TWIN-CENTER 

S88- Rückmeldebus 

S88- feedback bus 

Track occupancy reports transmitted with very low wiring effort by the LDT-Feedback Module RM-GB-8 via the 

s88-feedback bus to the TWIN-CENTER. 

. 





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twin-center_info_en - LDT

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