Associated Products:

DT602, DT602, DT602D, DT602D, DT602DE, DT602DE, EVOX, EVOX, EVOXD, EVOXD, PR4, PR4

KB1063: IPLing and Track Power with the DT602/D

This article was last updated on July 15, 2020, 11:50 a.m. | Print Article | Leave Feedback


  1. From time to time the latest DT602 family throttle firmware will be updated and will be posted on the product support page.  These updates may slightly modify the DT602's operation, based on customer feedback/requests and priority support issues discovered. If you are happy with the operation of your DT602, and have no issues or new features you may want, it is not required to perform an available update.

  2. All DT602 family throttles should only be firmware updated or IPL'd while plugged directly into a working LocoNet.

    • The Digitrax provided DMF file for field updating DT602's can be used for IPL of any variant of the DT602, DT602D or DT602E throttles.

  3. When performing any IPL on a LocoNet system it is best practice to disconnect all devices on the layout LocoNet except the Command Station and device being IPL'd, and the connection to the PC running the DigiIPL utility, such as MS100, PR3, PR4 etc. An onboard USB connection selected in DigiIPL for a DCS240 or DCS210+ or DCS52 will put the IPL file onto the working LocoNet.

    • Disconnect throttles and UR90/91/92/93, LNRP interfaces that are not being updated, and have no active mobile decoders selected or moving on the layout. The simplest thing is to disconnect the LocoNet cable to the layout, and plug the DT602's directly into the Command Station only. With the DCS52, Evolution Express system DCS210+ and DCS240 you can download up to three DT602's at once when using the built in Command Station's USB com port.

    • Taking care with LocoNet devices connected during any IPL process ensures least likelihood of any transient activity causing a disruption to the IPL data stream on the LocoNet data lines. IPL times may be a number of minutes, and updates are not often performed, so this precaution may save having to repeat the IPL process until the target device(s) successfully complete an IPL update.

  4. The DT602 family throttles have a download time that is typically over 4 minutes, so any interruption or electrical disturbance may cause inconvenience.  The download is about a 750,000 byte transfer and any bit lost/corrupted will cause the download to fail.  This can be recovered from easily by simply re-starting the whole download/IPL again, but is tiresome, so good practices will make things much easier.

  5. Only a matched Digitrax IPL capable product type, with its software version the same or below the one you are sending out from the selected Digitrax .dmf file will respond to an IPL cycle start.  There are a number of data security measures embedded in the IPL file, and any responding devices will not resume normal operation, and will remain in IPL download mode indication until a complete IPL cycle has occurred and all checks succeed.  For a DT602, IPL mode active is shown by all the numeric keys flashing green at about once per second, indicating the IPL is active and not yet completed OK. 

  6. Digitrax tests new product IPL stability and reliability using DigiIPL 2.2 from our web site and the correct product DMF file,  and the following environments: (a) running  Windows XP, Windows7 and Windows10 Operating systems with correct drivers, and (b) using a PR3, PR4, DCS240, DCS52, DCS210+ and MS100 (both DB9 +DB25 COM ports) LocoNet interfaces for the IPL target COM port selection.

    Digitrax successfully downloads multiple e.g. DT602's at the same time with no IPL failures, by following the care points noted earlier in this KB article.

    • Some other hardware and software combinations may provide a stable IPL download, but Digitrax is not able to confirm stability of any other IPL combinations.
    • All Digitrax IPL'able products will remain in IPL mode until successfully completing an IPL cycle.  If the update process fails, the device will remain in IPL mode and it will accept another IPL attempt.

    • If an IPL is not a required fix, but an optional feature modification, Digitrax can perform the IPL at the factory for a nominal charge.  To save shipping time and temporary loss of use, it is sensible to configure an IPL capability locally.

    • When using a power-sequencing USB port, such as a laptop, be sure system settings do not to allow the PC to power-save during the several minutes the IPL will be active.

  7. The Digitrax PR4 allows USB serial COM port access from a computer onto a working LocoNet that does not have inherent USB access from a PC.

    The PR4 is specifically designed to provide optically isolated/galvanic ground-loop protection to spread-out layouts needing multiple PC USB connections from multiple PC's. 

    The PR4 isolated LocoNet port side must have Railsync power provision and a LocoNet data line pullup, for the PR4's USB connection to be able to send and receive LocoNet data to/from the PC.  This is normally provided by almost any  LocoNet compatible Command Station (CS) running on a powered LocoNet network the PR4 is connected to. 

    • Without a CS the PR4 can still operate OK as a standalone DCC decoder Service mode programmer and Digitrax Sound programmer using a PC app such as SoundLoader, if a +12V supply like a PS14 is plugged into the PR4 DC jack, and a program track connected to the PR4 terminals for this.

    • If a CS is not available, you can "kit-bash" a workaround for a basic PR4 LocoNet data connection to one Digitrax device such as a; DT500 or DT602 type throttle to allow a LocoNet IPL or download of current firmware from the web site.

      (a) The device to be IPL'd should be plugged directly into a PR4's RJ12 port, and a CS LocoNet Data Simulation Cable plugged (see below) into the second RJ12 port.  There should be no other devices on this LocoNet wiring or two RJ12 ports.

      (b) With this configuration, the PR4 can now download an IPL file using the free Digitrax DigiIPL app, without requiring any CS.  This setup will support a single LocoNet device connection with less than about 10 feet total of LocoNet wiring. Do not use this arrangement with a CS, or more devices.

    • To make a CS LocoNet Data Simulation Cable for use with the PR4 without a command station:

      (a) Take a cable with a RJ12 6pin plug and strip back 3 to 4" of the other end to expose the 6 standard colored wires. Connect the BLACK and YELLOW LocoNet ground wires to the negative (-ve) lead of a 12 to 15Volt DC supply.

      (b) Connect the DC supply positive (+ve) to one side of a 1K 1/4Watt resistor, and then connect the other side of this 1K resistor to the RED and GREEN LocoNet data wires.  This provides a simple low-load data pullup.  The actual resistor value is not critical, and is best between e.g. 820 and 1.2K ohms for normal LocoNet speeds.

      (c) Connect a 100 ohm 1/4Watt resistor to the DC supply positive (+ve) wire and then connect the other side of his 100 ohm resistor to the LocoNet WHITE wire. This provides minimal power to allow the galvanic isolation logic to transfer data in and out of the PR4 when it operates with an app like DigiIPL selected as a COM port. Enjoy!
  8. Note that the Digitrax  IPL .dmf files incorporate several  internal levels of data-corruption protection and error detection mechanisms, on top of the usual PC file checks. The IPL .dmf files embed and automatically identify themselves, so target devices cannot miss-load the wrong Digitrax  firmware download.  The DigiIPL app does not control this check mechanism, it is inherent in the target devices and .dmf file structures.

    You cannot download a lower numeric Software Version (as e.g. identified by DigiIPL), so e.g.the DT602 IPL files incorporate a software Version AND a date shown on the power-on splash screen.  So it is now possible to identify and roll back to an earlier IPL feature set, at the same SW version level.  

    For example, if your DT602 is using S/W ver 0000.1 firmware, you may update to any "sub version" of S/W ver 0000.1 firmware.  And you may update to a different S/W version number so long as it's version number is greater than the current S/W version number.


Track Power:  In some system configurations (e.g. Duplex)  the DT602 may not be updated for the current Track power status, and if it writes back the state incorrectly, under some conditions it may unexpectedly shutdown track power.  To work around this, change the Command Station OPTION SWITCH 43 to CLOSED.  This ensures the track power will only be changed by an explicit Track power ON or OFF command.

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