Which RailCom decoder does what
Last updated
This page is under construction. The columns are settled; the rows are not. Every cell marked TBD is a fact we have not yet established, and a row whose source is TBD has not been checked against anything. Treat nothing here as confirmed until its source column says where it came from.
The RailCom introduction explains what each feature is for. The short version: a decoder that “supports RailCom” may send only its address, and the standard leaves most of the rest optional, so the only way to know what a decoder does is to look it up, which is what this table is for.
The list is ordered with the most functional tested decoders at the top: the more RailCom features a decoder has, the higher it sits, and untested decoders come last, greyed out.
One column needs a word of explanation. XPOM, extended programming on the main, is defined in RCN-214 and answered over RailCom as RCN-217 describes. An ordinary POM command reads or writes one CV, and reaching a CV above 1024 means first setting the index CVs 31 and 32. An XPOM command carries a 24-bit CV address, so every CV is reached directly, and it reads or writes up to four consecutive CVs at once; the reply is one 36-bit datagram holding all four values. RCN-214 gives the purpose as speeding up CV access in operation, and for a sound decoder with hundreds of CVs across indexed pages that is the difference between reading the whole decoder on the main in minutes and in a quarter of that. A decoder has to queue up to four XPOM commands and answer each only after the write has been done, so the command station can pace itself to the decoder. Few decoders support it yet, which is why it has a column.
A row describes one decoder model at one firmware version, because features arrive in updates. Where a maker documents a feature we say so; where we have measured it on the bench we say that; where the two disagree we will say which we believe and why. A row whose source is the maker’s manual marks a feature present only where the manual says the decoder sends it; a manual that says a decoder “can” send something, or says nothing, leaves the cell TBD.
Other people measure decoders too. The most thorough public survey we know of is the RTB4DCC decoder test page, which lists two dozen decoders by firmware with the replies, dynamic values and cutout timing each one produced. We do not copy its results into the table, because they are not ours and not the maker’s, but it is well worth reading before buying.
| Replies | Live values | Options | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Decoder | Ch 1 | POM | XPOM | DCC-A | Search | Speed | Load | Temp | Volts | Fuel | QoS | Dir | Hi-I | Source | Notes |
| ZIMO MN150 5.29 | Yes | Yes | No | Yes | Yes | Yes | No | Yes | Yes | No | Yes | Yes | TBD | Both | |
| ZIMO MX small decoders (MX600 to MX638) 40.x | Yes | Yes | TBD | TBD | TBD | Yes | Yes | Yes | TBD | TBD | TBD | TBD | No | Maker | |
| Doehler & Haass DH05C (also DH10C, DH16A) 3.15 | Yes | Yes | TBD | TBD | TBD | Yes | TBD | TBD | TBD | TBD | Yes | TBD | TBD | Maker | |
| Tams LD-G-43 manual 1.2 (06/2024) | Yes | Yes | TBD | Yes | TBD | No | No | No | No | No | Yes | TBD | TBD | Maker | |
| Lenz Standard+ V2 (10231-02) 77 | Yes | Yes | TBD | TBD | TBD | Yes | TBD | TBD | TBD | TBD | TBD | TBD | TBD | Maker | |
| ESU LokPilot 5 (all variants) 5.x | Yes | Yes | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | Maker | |
| TCS Non-sound decoders (T4X, K1D4 and others) 94 | Yes | Yes | TBD | No | TBD | No | No | No | No | No | No | TBD | TBD | Maker | |
| Train-O-Matic Lokommander II (Next18) 5.10.306 | Yes | Yes | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | Maker | |
| Uhlenbrock IntelliDrive 2 Next18 (73236) firmware TBD | Yes | Yes | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | TBD | Maker | |
| Dapol Imperium (2, 3, 5, 6) firmware TBD | No | No | No | No | No | No | No | No | No | No | No | No | No | Maker | |
| DCCconcepts Zen Black (8-pin) 42, no RailCom seen, maker to confirm | No | No | No | No | No | No | No | No | No | No | No | No | TBD | Test | |
| Digitrax DN163K4A (Kato N Glacier Express) firmware TBD, no RailCom seen, maker to confirm | No | No | No | No | No | No | No | No | No | No | No | No | TBD | Test | |
| Hornby HM7000 (all variants) 1.3.0 | No | No | No | No | No | No | No | No | No | No | No | No | No | Maker | |
✓ present✗ absent? not established. Source: M maker's documentation, T our bench, B both, ? none yet. A greyed row is untested: nothing in it has been checked yet. "No RailCom seen, maker to confirm" marks a decoder that sent nothing on our bench and whose maker has not yet confirmed it has no RailCom. Hover a heading for what the column means, or open the list below.
ZIMO MN150, firmware 5.29
Read against the RailCom chapter and the CV28 and CV99 tables of ZIMO's MS/MN manual, and checked on our bench on 15 and 16 October 2026 with a decoder new from the packet on firmware 5.29, which is ZIMO's current release (5.29.0, 24 July 2026). The maker documents the address broadcast, CV reading on the main, DCC-A, the speed, temperature, track-voltage, quality-of-service and direction-state reports, and the on-track search; the bench saw all of them. Load is No because the manual lists motor current as planned and the bench saw no load report. Fuel is No because it is in neither. XPOM is No because an XPOM read got an acknowledgement but no data; the manual does not mention it. High current is TBD: the manual gives CV28 bit 6 for large-scale decoders and does not say whether the MN150 has it.
ZIMO MX small decoders (MX600 to MX638), firmware 40.x
Read against ZIMO's MX small decoder manual, latest version 19 August 2024, whose edition list runs to software version 40. The RailCom chapter says these decoders send their address, CV content on demand, and "actual speed in kph, load and decoder temperature"; CV158 bit 2 selects the standard speed report (ID 7) over ZIMO's older one. CV28 bit 6, high-current RailCom, is marked "MX699 series only", so it is absent here. The manual does not mention DCC-A or the on-track search; ZIMO's newer MS and MN decoders have those. The MX line is still sold but is being replaced by MN. Not yet on our bench.
Doehler & Haass DH05C (also DH10C, DH16A), firmware 3.15
Read against the English DH05C/DH10C/DH16A manual, valid from firmware 3.15, linked from the product page. The feature list gives "locomotive address feedback in DCC mode, RailCom, reading CV values using POM, speed feedback, QoS feedback of the track signal quality", and Supplement 7 explains the speed report in km/h, calibrated through CV135 and CV136. CV28 has channel 1, channel 2 and "dynamic channel utilization". The manual does not mention DCC-A, direction state, temperature or voltage. Not yet on our bench.
Tams LD-G-43, firmware manual 1.2 (06/2024)
Read against the German LD-G-43 manual, version 1.2, June 2024. It states the decoder is a RailCom transmitter meeting RCN-217 for mobile decoders, supports automatic logon under RCN-218 (DCC-A, CV28 bit 7, on by default with CV28 = 131), and lists exactly one dynamic value it can send: the reception statistic, enabled by CV10. Because the manual names that as the only dynamic report, speed, load, temperature, voltage and fuel are marked absent. XPOM, direction state and the on-track search are not mentioned. Not yet on our bench.
Lenz Standard+ V2 (10231-02), firmware 77
Read against Lenz's Standard+ V2 manual, 5th edition, November 2020, which gives the version number in CV7 as 77. Its RailCom section says that besides the locomotive address "other data (e.g. speed, CV content)" is sent, and CV28 bit 0 releases channel 1 for the address broadcast and bit 1 channel 2 "for data and command acknowledge". Nothing else is listed, so the other columns are TBD. The Silver+ and Gold+ manual (7th edition, October 2020) has the same CV28 table and no RailCom chapter. Not yet on our bench.
ESU LokPilot 5 (all variants), firmware 5.x
Read against ESU's LokPilot 5 family manual, 8th edition, January 2023, which covers firmware from 5.3.128 (the current firmware is 5.14.183). The RailCom chapter says the decoder broadcasts its address, answers CV reads on the main, and "can transmit status information such as motor load, current draw of the motor, temperature etc.", without saying which of these the firmware actually sends, so those are TBD. CV28 has bits for channel 1, channel 2 and RailComPlus (bit 7); the manual does not mention DCC-A, XPOM or the on-track search. A third-party test page (rtb4dcc.de) reports a LokPilot 5 answering XPOM and sending speed; we have not checked that ourselves. Not yet on our bench.
TCS Non-sound decoders (T4X, K1D4 and others), firmware 94
Read against the RailCom page of TCS's own documentation wiki, which lists the decoder families that support RailCom and says any decoder not listed never has. Channel 1 carries the address (short address only before version 97) and channel 2 the data and acknowledgements; CV28 bit 7, automatic logon per RCN-218 or RailComPlus, is marked "under development" and off by default, so DCC-A is absent for now. Dynamic data such as temperature and fuel is described as "still being explored", so those columns are absent too. Version 94 was the production firmware in March 2023. Not yet on our bench.
Train-O-Matic Lokommander II (Next18), firmware 5.10.306
Read against the Lokommander II Next18 manual, document version 0.5.07, June 2022, for firmware 5.10.306, hosted by Tillig. Its RailCom chapter describes channel 1 carrying the address and channel 2 carrying POM read and write results, with CV28 bits 0 and 1 enabling them. The chapter's opening says a decoder "can" send speed, temperature and load, but does not say this one does, so those are TBD. DCC-A is not mentioned. Not yet on our bench.
Uhlenbrock IntelliDrive 2 Next18 (73236)
Read against the German manual for article 73236, 2nd edition, February 2019. It says the decoder is RailCom and RailCom Plus capable, with CV29 bit 3 enabling RailCom and CV28 bit 7 RailCom Plus (default 131), and describes CV index pages for RailCom read-back. No dynamic values and no DCC-A are mentioned. Not yet on our bench.
Dapol Imperium (2, 3, 5, 6)
Dapol's product pages for the Imperium 3, 5 and 6 state "RailCom is not supported" and give NMRA and MOROP DCC standards as the compatibility. No manual is linked. Every column is therefore absent on the maker's word.
DCCconcepts Zen Black (8-pin), firmware 42
No RailCom seen on the bench; awaiting the maker's confirmation that the decoder has none.
Bench only, 16 October 2026, an 8-pin NEM 652 Zen Black reporting firmware 42 in CV7. With RailCom enabled (CV29 bit 3) and both channels enabled in CV28, driven and left over a minute after power on, the decoder sent nothing in any of 1,446 cutouts. Every feature is therefore marked absent, but this awaits the maker's confirmation that the decoder has no RailCom transmitter, rather than this one being faulty or needing some other setting. The maker's Zen manual mentions RailCom only as the CV29 option, which it recommends leaving off, and lists no RailCom features. Returned to factory values afterwards.
Digitrax DN163K4A (Kato N Glacier Express)
No RailCom seen on the bench; awaiting the maker's confirmation that the decoder has none.
Bench only, 18 October 2026, the board-replacement decoder fitted to a Kato N scale Glacier Express. Driven on the bench with the command station making a cutout after every packet, the decoder sent nothing in any cutout. Every feature is therefore marked absent, but this awaits the maker's confirmation that the decoder has no RailCom, rather than this one being faulty or needing a setting. The maker's instruction sheet does not mention RailCom; the only feedback it describes is Digitrax's own Transponding, off by default and enabled through CV61, which is a different system and is not heard by a RailCom detector.
Hornby HM7000 (all variants), firmware 1.3.0
Read against the HM7000 Series Decoders Reference Manual, version 1.3.0, November 2023, linked from Hornby's HM|DCC guides page. Its CV29 table marks bit 3, RailCom enable, as "Not supported", and the text says "RAILCOM is not supported in HM7000 decoders" and that the decoders do not support RailCom read-back in POM mode; configuration is read back over Bluetooth instead. Every column is therefore absent on the maker's word.
What the columns mean
- Decoder
- Maker and model, with the firmware version the row describes beneath them; a feature can arrive in an update. "No RailCom seen, maker to confirm" means the decoder sent nothing in any cutout on our bench, so every feature is marked absent, but the maker has not yet confirmed that the decoder has no RailCom rather than this one being faulty.
- Ch 1: Address (channel 1)
- Broadcasts its address in channel 1
- POM: CV read (POM)
- Answers a CV read on the main in channel 2
- XPOM: XPOM (extended POM)
- Reads or writes four consecutive CVs in one exchange, with a 24-bit CV address that reaches the indexed CV pages directly
- DCC-A: DCC-A
- Automatic logon per RCN-218
- Search: Track search
- Answers the on-track search after a power cut
- Speed: Speed
- Reports real speed
- Load: Load
- Reports motor load
- Temp: Temperature
- Reports its temperature
- Volts: Track voltage
- Reports the track voltage it sees
- Fuel: Fuel
- Reports container (fuel, water, sand) levels
- QoS: Reception statistics
- Reports the share of packets it missed
- Dir: Direction
- Reports its direction state
- Hi-I: High current
- High-current RailCom option
- Source
- Where the row's facts come from: M, the maker's own documentation; T, our bench; B, both; or ?, not yet established.
- i
- Opens the row's notes and the maker document it was read against.
In every feature column a tick means present, a cross absent, and a question mark not yet established. A blank is never used, so a missing fact is always visible.