z21 Review: Booster Light and Detector

It has been awhile (more than 1 year to be exact) since I touched my z21 digital controller. It lied packed neatly in the original packing. This means I have missed many firmware updates (hmm …. not a good thing to do). Anyway, even though I am not actively working on my layout, this does not mean that I have gave up the hobby. No, no way sir. You will just have to be a bit patient with my progress. This morning, I posted on a friend’s Facebook that I have 8 modules and if I work on one each year, I should have my layout completed 2023! Just in time to enjoy my retirement with a completed layout. Oh yes, it is a segment layout by the way.

When I was looking at the Roco 2016 catalog the other day, I saw a few new products for z21/Z21. Roco/Fleischmann (both companies taken over and run by Modelleisenbahn München GmbH) will offer accessories to their current z21 white and Z21 black digital control centers. Upcoming products are Z21 Booster (Roco Art. 10806), Z21 Dual Booster (Roco Art. 10807), z21 Booster light (Roco Art. 10805), Z21 Detector (Roco Art. 10808). The first two are power boosters that complement their current Z21 Black digital control center (Roco Art. 10820 EU-version 220/240V). Please take note that these 4 accessories are built for 220/240V power supply. We will most likely see the US version later in the year or next year. The US-version of Z21 Black (Roco Art. 10822 110V) was introduced some time spring last year.

In this post, I am interested to review (on paper at least) and discuss about the last two accessories – Z21 Booster light and Z21 Detector, although I do not have the products yet. z21 white is sold as part of HO- or N-scale starter packs. On eBay, you can get the z21 white for 160 Euro as modellers. Both Booster light and Detector will come in white (as shown in promotional material). Visually you can relate them to the z21 white control center. Nonetheless, to be on the safe side, I have written to Roco and received their confirmation that both Booster light and Detector can be connected to the z21 white via respective B-Bus port for Booster and R- or CAN-Bus ports for Detector.

Z21 BOOSTER lightProduct illustration: (L – R) separate DC power for the booster light, power to track (separate power district) and 2 B-Bus (booster bus) ports.

However, you will notice that the main controller has only 1 B-Bus and 1 R-Bus port (even Z21 black has only 1 B- and 1-R bus port) but the Booster light will have 2.



Does this mean that multiple Booster light can be daisy-chained or connected in serial? Another clarification question for Roco.

At least for now, we can safely say that the Booster light can be connected to the z21 white, which would be a good news for those who want to continue to use their z21 white but need additional power district. Like me. I would need two power districts for my german160 segment layout. This Booster light has 3A output (non-adjustable voltage) and supports RailCom cutout (i.e. (allows use of RailCom*-track occupied detector) and terminal loop feature with short-circuit detector.

The Detector itself has 2 R-Bus (Response bus) and 2 CAN-Bus ports. For the Detector to have 2 ports is understandable. When you connect one Detector to the main controller, which then communicates with the Z21 app in your smart device or PC, you need to have one free port to connect to additional Detector. Each Detector can connect up to 8 track-occupancy sections. For more sections, you need multiple Detectors and each Detector must be able to connect to the main controller. The only way to do this is ….. yes, DAISY-CHAINING the Detectors together!


The Detector monitors each section by way measuring power drop on each section and relay the occupied message back to the App or PC. It also supports RailCom-detector for loco identification.

For now, looks like Roco/Fleischmann would allow modellers to have one more power district and able to detect track occupancy. They must have read my german160 blog (*wink*) as I was planning to have extra power district and was looking for ways to implement track occupancy.

Something that fellow modellers using z21 white can look forward too. We will see how the price and performance/features measure up to alternative products.

Is this something you are looking forward too? Would love to hear your feedback.


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