QSI KeepaliveThis page under construction This subject has come up before, so I guess it is time to address it.One of the Titan pinout diagrams shows a LENZ keepalive connected, and it is the 3 terminal type. Most 3 terminal ones are connections to the keepalive capacitor (with or without charge current limiting resistor and requisite discharge bypass diode) and 1 line to "enable" the keepalive.(more specific data on various keepalives will follow) How to connect:Start the the LS Titan drawing:You will see that at the bottom, there is a Lenz Power 3, with the plus and minus to J19 and J20... these connections are to C32, which is a 220 mfd 5v cap (the other 2 electrolytic caps are 35v (rectified track power), and 6.3v (must be filtering before microprocessor 5v power supply)So, right off the bat, it seems that the motors will not be run with the keepalive. A guess on audio, might work, but the amps should be running from a higher voltage supply to get the claimed wattage.The 5v lamps might work, not sure if the 5v pin on the Titan is this same 5v. The keepalive control pin is on J2-11, which is port 10 on the LS Titan (on the titan U HO decoder, the documentation says defaults to light port 10 also)so now, the next part of the investigation is reading out what FEATURE ID the default firmware has on port 10This should be CV 115.PI.SI, and reading all 115 CV's, look for the one that is pointing to port 10, in the LS case, I found this was step lights.Does not seem to make sense yet... but also Colin S found that there is a CV (which I had not investigated) that has a bit for enabling a keepalive: CV56.0, bit 6 (section 5.8.1) and apparently only available on Q3 FX-U.... but the diagram above from QSI shows a large scale titan...So, time to experiment on port 10.. may want to set some of the DCC timeout CV's (how long the Titan waits for a DCC signal.)Look at CV58.10.x, this is a 2 byte value of stopping distance in scale feet, up to 65,535... so that might also need to be set to make sure the loss of DCC does not make it stop immediately. The default value is zero..
QSI O scale TitanThis page is under construction. I've got to add the currrent handling specs, There are 12 lighting outputs, including one that is high current for a smoke heater elementNaming the connectors: (Please ignore the wire colors, apparently there were several versions of harnesses supplied.)P1, pin one is in the extreme upper right of the above and below pictures. It has 8 pins.P2, pin 1 is next, in both pictures this is a green wire. It has 8 pins.Next are two 2-pin connectors, these I'm working on a "translation" that maps the ports as defined in the manual to the wires on the top 2 connectors(most of this information from Jerry Davis, thanks!) Quantum Titanmanual port #FX-DO port #per O scale docs FX-DO plug / pin number FX-DO wire color NotesThe FX-DO port number is actually meaninglessUPPER BOARD L10 L1 P1-1 red L11 L2 P1-2 orange L12 L3 P1-3 blue L5 L4 P1-4 white L6 L5 P1-5 yellow L7 L6 P1-6 gray +5V P1-7 black GND P1-8 violet L8 L7 P2-1 red L1 L8 P2-2 orange L2 L9 P2-3 blue L3 L10 P2-4 white L4 L11 P2-5 yellow L14 L12 P2-6 gray High current smoke +5v P2-7 black GND P2-8 violet P5-1 speaker 2 plus P5-2 speaker 2 minus P6-1 speaker 1 plus P6-2 speaker 1 minus P6-1 +5v P6-2 chuff cam P6-3 gnd P12-1 reed switch (for reset/programming) P12-2 gnd for reed (convenience)LOWER BOARD P1-1 red track right P1-2 black track left P1-3 orange motor plus P1-4 brown motor minus P2 - see note duplicate of P1, so dual pickups and dual motors easy to connect P3 - see note 4 pin connector labelled: DL - unknown P5 4 wire connector for G-Wire flat cable P6 smoke heater P6 smoke ground P14 labelled: DL (may be addional connection for extra lighting co-processor, or perhaps high speed DL port h
MTC21 / NMRA / NEM decodersThis is an interesting subject, as the concept of "logic level" outputs on decoders is still relatively new to US users.The impetus for this page is a friend, who is an installer, had questions about interfacing to a SoundTraxx decoder, and he said, "I hooked up lights to the AUX outputs, and they all went on and I could not turn them off. I responded that perhaps (since it was a 21 pin interface, which I know originated in Europe, they could be logic level outputs. What's that was the response, and the journey started.Overview:The history of this decoder interface goes way back. I don't feel like researching all the dates, but there was an NEM standard 658 interface called "Plus-X" with a dual row 21 pin connector, and it was related to an NMRA standard, which still exists, but has proven to be a Cul de Sac.... going nowhere.Recently SoundTraxx started making decoders that met the NEM standard (European NMRA sort of) and as of about 2024, the standard has changed, and finally the NMRA standard is harmonized with the NEM standard. Unfortunately, many, no make that MOST decoder manufacturers just say "meets NEM standard". BAD!I'm concentrating on just ONE standard for 21 pin decoders, the MOROP/NEM 660 standard, also called MTC21, which is harmonized with the NMRA 9.3.1.1 standard. I'm not interested in the older and even more messed up stuff.Links to these standards:NMRA 9.1.1.3 MTC21 https://www.nmra.org/sites/default/files/standards/sandrp/DCC/S/s-9.1.1.3_21mtc_decoder_interface_3.pdfNEM 660: https://www.morop.org/images/NEM_register/NEM_E/nem660_en_2022.pdf New concepts:For most people, the ability to "change" what a decoder pin does is not new, but note that this is becoming more prevalent, so note that as you review.The biggest "new" thing is that many "outputs" are now "logic-level" that matches TTL computer logic voltages on digital logic chips. You can no longer just hook lights to ANY decoder output.Outputs: (normal/amplified)First a little explanation: Decoder "outputs" are usually really an "input" from the sense of electrical conventions. In the old days (pre-digital logic), ON was the presence of positive voltage, and ground and minus were the same. So if you put a voltmeter on an "output", when you turn it on, you got voltage (as reference to ground). The current flows "out of" the decoder.But, when we started getting in gear with DCC decoders, all of a sudden things were reversed. You used the blue wire which was actually positive, hooked up your lamp/LED, and the other end went to the decoder "output". To turn the lamp on, the decoder actually GROUNDS that pin.Why? A result of the process of making integrated circuits... turns out that it's cheaper and easier to make the open collector NPN transistor than the "positive switching" PNP transistor... actually pre-dates IC's, actually cheaper to make standalone transistors in NPN.So all of our "outputs" are actually "inputs" that are grounded when active. So most people are used to this, know the blue wire is common, and some even realize it is positive voltage. Just part of understanding how things work.Enter logic-level "outputs":So manufacturers realized early on that sometimes you connected something smarter than just a light bulb to a decoder. Probably the best first example was the SUSI bus, for sound units, when no motor decoders had sound in them... the SUSI bus allowed communication for configuration and data like motor speed or load to be communicated."logic level" signals were used, there were variations, but today it means "TTL signal levels", which are the dreaded 1's and 0's of digital communication. a zero is <=0.4 volts, and a one is >= 2.4 volts. So these outputs clearly do not supply "on and off" as a light bulb would want to see it.Conversion of logic-level "outputs" to the familiar decoder outputs, a.k.a "amplified" outputs.So since logic-level outputs are defined, there needed to be a term for "normal", connect to ground outputs, and the term is "amplified" outputs. It's really a misnomer, but since it does not belie the radically different characteristic of the output, but "amplified" it is.How to convert "logic level" to "amplified"? Simple, you use a transistor as a "power switch". This is actually what is already done in most decoders internally. The logic output is connected to the base of a transistor (that is the transistor's "control pin"), and the emitter and the collector are the 2 parts of the "switch", one goes to ground, the other is your new "output" pin.In fact there are commercial products to do just this for your decoder with logic levels when you want to run a bulb, or LED or actually anything that needs power.OK, OK, enough lecture, get to the meat!The following chart shows a "translation" from the decoder pins to the actual function/description on the decoder:Deviations from the 9.1.1.3 / NEM 660 will be highlighted in yellowI've selected 4 current/representative decoders:TCS Wow121 decoders - https://drupal.tcsdcc.com/pinout#21, https://52b7f1f3-d14f-4a29-9386-16e084d54015.usrfiles.com/ugd/52b7f1_06948ecc54324a58bcfdc083df8af2bc.pdfSoundTraxx BLU-21PNEM8 / TSU-21PNEM8 - https://soundtraxx.com/content/Reference/Manuals/Tsunami2/Installation-Guide.pdf Note: just a pinout, NO descriptions, and NO reference to whether this meets the 9.1.1.3 standards or not, really crappy documentation. The note says this is an NEM decoder, and not an NMRA decoder... this must have been written in 2017 or before. ESU Loksound 5 - 58419, 58429 and 58449 ESU 21MTC decoders (still trying to narrow this down) 58429: https://www.esu.eu/en/downloads/instruction-manuals/digital-decoders/Zimo MS440C / MS440D - LL = logic level Nmra / NEM pinNmra 21MTC 9.1.1.3 /MOROP/NEM 660 standards as publishedTCSWOW121Soundtraxx MTC21 58419ESU MTC21 Loksound 5 Zimoms440cms440dNote1Sensor-input 1Alt AUX7CAM1 (chuff input) not used wheel sensor / AUX10 LL Input 1 /Alt F10“amplified” if not used as input. Should be used for input as chuff trigger2Sensor-input 2Alt AUX8 not used not used AUX7LLinput 4 /alt F09“amplified” if not used as input.3AUX6F6FX8 AUX6LLFO6“logic level”4AUX4F4FX6 AUX4LLFO4“logic level”5Train bus clockalt AUX9 not used not used SUSI clk /AUX12 LLSUSI clkalt FO7servo“logic level” for communication6Train bus dataalt AUX10 not used not used SUSI data /AUX11 LLSUSI dataalt FO8“logic level” for communication7F0rF0rF0r F0rF0r“amplified” normally rear headlight8F0fF0fF0f F0fF0f“amplified” normally front headlight9Speaker ASpeaker +Speaker SpeakerSpeakerImpedance must be documented by mfg10Speaker BSpeaker -Speaker SpeakerSpeaker 11 Index pinNmra / NEM pinNmra 21MTC 9.1.1.3 /MOROP/NEM 660 standards as publishedTCSWOW121Soundtraxx MTC21 58419ESU MTC21 Loksound 5 Zimoms440cms440dNote12Vcc (1.8-5.7v) not used not used VCC??+5v200maReference voltage not mandatory13AUX3F3FX5 AUX3FO3“logic level”14AUX2F2FX4 AUX2 FO2“amplified”15AUX1F1FX3 AUX1 FO1“amplified”16V+Positive commonPositive common U+ common Positive common Rectified track voltage17AUX5F5FX7 AUX5 FO5 “logic level”18Motor 2 / -Motor -Motor 2 gry left motor left motor - 19Motor 1 / +Motor +Motor 1 org right motor right motor + + for loco fwd20GNDGNDGND GND GND Actual "normal" negative / minus / ground21Track leftLeft Rail -Track leftTrack leftTrack left 22Track rightRight Rail +Track rightTrack rightTrack right Converters / aids for logic-level conversion There are a number of solutions, but I'm only going to be specific on one solution, and really the best one in my opinion.Decoder BuddyThere are 2 models that will convert logic-level outputs to "amplified" outputs, the V1 and V5(Pictures are to follow)The V1 has "amplification" on 4 pins: (the parenthesis refer to the description for NEM 660 / NMRA 9.1.13 specifications)13 (AUX 3)4 (AUX 4)17 (AUX 5)3 (AUX 6)Note:Note that I am using the new standards, so if your decoder does not conform, then you need to check which pin has an "amplification" transistor, and use that outputMost decoders are not perfect in following the standard, so they were probably designed to the older NEM / NMRA standards.SoundTraxx in particular renumbered the AUX "sequence", and the mapping is not easy to find, they have the worst documentation.this should give a total of 8 "amplified" outputs ( 4 from DB, and 4 stock)The V5 has "amplification" on 8 pins:(the parenthesis refer to the description for NEM 660 / NMRA 9.1.13 specifications)1 (AUX7) (according to the standard, used as AUX 7 is already "amplified")2 (AUX 8) (according to the standard, used as AUX 8 is already "amplified")3 (AUX 6) 4 (AUX 4)5 (AUX 9) 6 (AUX 10)13 (AUX 3)17 (AUX 5)Note:note that I am using the new standards, so if your decoder does not conform, then you need to check which pin has the conversion transistor, and use that outputMost decoders are not perfect in following the standard, so they were probably designed to the older NEM / NMRA standards.Note that pins 1 & 2, if the decoder meets the standard, should already be "amplified", but this does no harm.apparently stock, there are 12 2.2k resistors, so that covers the 8 amplified (from DB) pins, and the 4 pins that are amplified by the decoder "stock" (pins 7,8,14,15), so properly set up, you have up to 12 "amplified" outputs using a decoder and DB V5 The bottom line:You need to be SURE of what standard your decoder is following, and double check their literature.Then relate their "name" to a pin number... not ONE decoder at this time (August 2025) is perfect in matching the standard.The Decoder Buddy is a great help, saves space and time and frustration.As time goes on, I would assume everyone will offer decoders that meet the standards, which should reduce the confusion and effort to be sure of what is what.But, I doubt that ALL the logic level outputs will ever have on-board optional amplification, thus Decoder Buddy is indeed your "buddy"! Notes on TCS Wow121 decoders:Specified only as "21 pin MTC", 8 function, including f/r headlights. Meets standards well, only missing one sensor input, and the optional AUX 7,8,9,104 amplified outputs, 4 logic level outputs.Notes on SoundTraxx Blunami/Tsunami 2 decodersOh my God! Absolute worst documentation, and no clue of what pin does what. The installation and wiring guide says:21-Pin NEM connector interface, no mention of WHAT NEM standard they meet (which turns out to be NEITHER)Also, "SoundTraxx 21-Pin NEM decoders are designed for use with factory supplied motherboards which support the NEM specifications. Our decoders are notintended for use with 21-Pin NMRA standard sockets.Seriously WTF? They cannot update their documentation to reflect NMRA standards, or NEM standards, or what standard IF ANY they meet? The only documentation is reflected in the chart above.The 2 sensor inputs are NOT SUPPORTEDIt is 8 function, BUT for some reason SoundTraxx renumbered F1-F6 to F3-F8 (why?)No indication on the site which outputs are amplified and which are logic level. I would assume same, F0f, F0r, F3, F4 amplified, F5-F8 logic, but need verification.There's references that FX5-8 configuration is not on ALL decoders, no telling which!Terrible documentation, lack of information, renumbering outputs away from standards, and specifying they do not meet NMRA standards.Notes on ESU decoders:There is a lot of variation on the 21 pin decoders, 58419, 58429, 58449, look carefully when you choose. There's more differences than just what outputs are logic level.In any case, for some reason, ESU has weirdly renumbered the outputs, but this must be a leftover from the previous standards.More flexibility and more outputs than the TCS or SoundTraxx decoders.Note there are more functions on the decoder solder pads, so if you use just the 21 pin interface, you have up to 12 outputs, 14 if you use the solder pads. AUX 8 & 9 only on the solder pads.Some of the solder pads are replication of an output pin, but amplified. Pretty nice, but sort of blows up using the socket. Notes on Zimo decoders:Overall, the most compatible of the lot, and the most flexible, with up to 4 inputs, regulated 5 volts available, etc. (I'm a fan, sorry!)
DCC Service Mode Tips 4 different official modes: address mode - outdated, only updates CV1. For really old stuff, and if this mode is attempted on a newer decoder, it's possible that it does not update CV19 and/or CV29. Think original LGB stuff. (physical) register mode - old stuff again, and old decoders had registers that corresponded to cvs 1,2,3,4,7,8,29. No long address support page mode - extension of register mode. Uses register 6 as an index, and using 4 other register values, yielded 1024 cvs effectively... Often this has to be used for old decoders, or really dumb ones like switch machine controllers, or old weird stuff from europe direct mode - what is mostly used today... the standard states 1024 cvs