Digitrax Advanced Throttles

To clarify the differences between the various throttles, I have put together a table that summarizes their features. In some cases, the information below conflicts with what is on Digitrax's own specification sheets from their web site. In such cases, this is because I have determined the values in the table from direct observation.

This table is not intended to describe the specific features in detail-- it is a comparison table, not advertising material or user instructions.

An "advanced" throttle is any Digitrax throttle that has a display.

Digitrax "utility" throttles are described on a page of their own.

Manufactured 2006-
2010- 1996-
Can act as a command station 1 1 - 2 - - - -
Native 2-Digit/4-Digit Addressing3 2/4 2/4 2/4 2 2/4 2/4 2/4 2/4
Number of Functions Supported4 135 29 9 5 9 13 29 29
Full Numeric Keypad - - -
Infrared Wireless Capability - - 6 -
Simplex Radio Capability Available (R)7 - - - -
Duplex Radio Capability Available (D) - - - - - -
Build/Break Down Consists
Program Decoders
Full Decimal Numeric Operations8 - -
Descriptive Prompts for Throttle Setup Options9 - - - - - -
Fast Clock Display - - -
Recall Stack Size (User-selectable) - - - - 4/8/16 4/8/16 4/8/16 4/8/16
Throttle Knobs 1 1 2 2 2 2 2 2
Stationary Decoder Control
Highest Stationary Decoder Address 999 999 999 127 999 999 999 2048
Cab Signals10 - - - - - -
Track Power On/Off
Throttle Power On/Off Switch - - - - - - -
Transponding Find Function - - - - -
View Detection Section Status ("Input Mode")11 - - - - - - -
Flashlight - - - - -
Downloadable Firmware Updates - - - - -
Slot Zeroing12 - - - - - - -
Device Query13 - - - - - - -
Prompt for Multiple Throttles Controlling Same Loco14 -
Supports Expanded Slots Mode (more than 120 throttles)15 - - - - - -
"StealZap"/Prevent Multiple Throttles Controlling Same Loco16 - - - - - -
Changeable LocoNet Throttle ID17 - - - - - -
Supports 2-digit Address Aliasing18 - - - - - -



1 The Zephyr and Zephyr Extra are designed, first and foremost to be command stations. They are listed here because they include integrated throttles. Properly configured, they can be used as an additional stationary throttle on a LocoNet-equipped layout where the Zephyr or Zephyr Extra is not being used as the command station. The feature specifications listed in this table apply only to the built-in throttle.  
2 The DT200 contains command station firmware to serve as a command station as part of the former Digitrax Big boy starter set, much in the same way that an NCE PowerCab can act as its own command station. When A DT200 is connected to another command station, it simply acts as another throttle on the system.  
3 The earliest DCC decoders only supported addresses from 0 to 127. Because of how these were represented internally in the decoders (and partially because some early DCC systems only supported addresses up to 99), these were referred to as "two-digit" addresses. The DCC standard was soon extended to be able to support addresses to just over 10,000. Most DCC systems marketed in the US can support addresses up to about 9999, as four-digit locomotive numbers are common in the US. Digitrax command stations treat all addresses below 128 as "two-digit" addresses, and all addresses above 127 as "four-digit addresses." Other brands' command stations handle this distinction in their own ways.  
4 On this chart, I count reversible headlights (controlled by Function 0, by default) as a single function. Some people prefer to count them as two functions, since you can set the behavior of the forward headlight and the reverse headlight separately on most decoders. In that case, you would increase the function count by one. From a throttle perspective, though, both are still controlled by F0, by default.  
5 When functioning as a throttle, the DCS50 only offers access to 13 functions. When used as a command station, any external throttle connected to it can control as many functions as the external throttle supports.  
6 While the other "infra-ready" advanced throttles all came factory-equipped for infrared remote control, the original DT100s did not. In the DT100 line, only the DT100IR model has infrared capability.  
7 This row indicates whether the throttle was ever sold with that capability, or whether a radio upgrade was available at one time. It does not mean that a radio upgrade is currently available from Digitrax.  

Digitrax's first two "Advanced" throttles, the DT100 and DT200 used an LCD display that had a limited number of digits and had an internal processor with a limited amount of memory. To accommodate these, it was often necessary to enter values into the throttle using hexadecimal notation (base 16- where numbers are made up of the digits 0-9 and the letters A-F). This particularly affected decoder addresses from 100 to 127, which were entered in an unusual hybrid form. Similarly, values being programmed into CVs in decoders had to be entered using hexadecimal. This was not intuitive to most people outside of the computer engineering community, and contributed to early Digitrax equipment having a reputation for being overly difficult to use.

Since the release of the DT300- and DT400-series throttles in 2000, it has not been necessary to use hexadecimal notation when using Digitrax equipment on a day-to-day basis, although some competitors still like to use the "Digitrax uses hexadecimal" line as a marketing tool. Throttles from the DT300-series forward, default to using familiar base ten (decimal) numbering, but still can use hexadecimal values for programming CVs in decoders. The Throttle ID number in the DT402- and DT500-series throttles is a hexadecimal number, but since this is an ID tag, rather than a value that has any meaning other than to be different from throttle to throttle, this is not a signficant burden. Otherwise, since 2000, use of hexadecimal numbers has not been a requirement to run trains using Digitrax throttles or perform decoder programming.

9 Starting with the DT300-series throttles, it was possible to customize some of the characteristics of an Advanced throttle. This included setting the intensity of the LCD backlighting, setting whether turning the control knobs makes a clicking sound, and several other features. The DT300- and DT400-series throttles only referred to their options by an "option number" that didn't have any intuitive relationship to the feature the user was trying to change, and required the user to calculate a numeric value to set the desired behavior. Starting with the DT402-series throttles, setting up the throttle options is now done using descriptive text-based prompts and answering Yes/No-type questions (where appropriate) or entering simple numeric values.  
10 The LCD display on every Advanced throttle since the DT300 has the elements to display cab signal indications, however only the DT402- and DT500-series throttles have the internal software to actually support this. Implementing cab signaling requires that each throttle be given its own Throttle ID number, and requires the use of computer software. Automated cab signaling usually requires installing additional detection hardware as well.  
11 Input Mode is a feature that permits DT500-series throttles to query the status of a detection section, as reported by a BDL168, BD4, or similar LocoNet-enabled block detector. This can be useful for setting up and testing detection.  
12 Slot Zeroing is a feature that allows a DT500-series throttle to force the speed to 0 for all locomotives currently occupying slots in the command station. Generally it would be used at the end of an operating session, when all other throttles have been shut down.  
13 Device Query is a feature of a DT500-series throttle that allows a user to look up and scroll through statistics stored by an Advanced LocoNet device. At this writing, only the DCS210 and DCS240 command stations are Advanced LocoNet devices.  
14 This is the "Steal?=Y" message on DT300-series and later throttles, the "STLo" message on the DCS50 and DCS51, and the "ST:3x" message on DT100-series throttles. Pressing the "Y" key gives the throttle control of the locomotive, but it may also leave another throttle with control of that address, too, which can cause erratic operation. For this reason, I always recommend pressing the "N" key, and finding out which other throttle is already set to control that address. Once located, you can either use that throttle, or dispatch the address off of it so that you can acquire it with the throttle you started with. The moral of the story is to always dispatch a locomotive's address when you are done using it on a throttle, as part of "putting away one's toys."  
15 Expanded Slots Mode is a feature of the DCS240 command station that permits it to support more than 120 throttles in use on a layout at once. While up to 120 older throttles can be used when Expanded Slots mode is being used, any throttles beyond that 120 throttles must currently be DT402- or DT500- series throttles (DT402 throttles require version R21 or later firmware). Each of these DT402- or DT500-series throttles must be assigned its own Throttle ID value for this to work. Expanded Slots Mode supports throttles that are tethered, or using Duplex radio. Expanded Slots Mode is not supported for Simplex radio or infrared operation.  
16 StealZap is a feature that can be used to prevent multiple throttles from taking control of the same locomotive address at once. It only works in Expanded Slot Mode (which requires a DCS240 command station), and requires that the throttles each be given their own Throttle ID number. For DT402 throttles, this requires firmware version R21 or later.  
17 Changing the LocoNet Throttle ID number to give each throttle a unique value makes it possible for other LocoNet devices, such as the command station or signaling accessories, to distinguish between different throttles and to direct LocoNet commands or messages to specific throttles. If you intend to use Expanded Slots Mode or cab signaling, you must give each of your DT402- or DT500-series throttles its own (unique) Throttle ID number.  
18 Some early decoders supported only 2-digit addresses. With a DT100 or DT200 throttle and a DCS100 or DCS200 command station, it was possible to define a 4-digit number (matching the number on the locomotive's cab) as an alias for a 2-digit address. Once this was done, the user would not need to remember the 2-digit address of the decoder, but could simply call up the locomotive by the number on the locomotive's cab. This functionality is not supported by any command stations except the DCS100 amd DCS200.  


--Fritz Milhaupt, Aug. 2017


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