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Roco Z21

Z21/z21 Firmware


  • LocoNet sensor modules from Digikeijs seems not compatible with the Z21.


  • Track power voltage, load and CS temp. in status bar.
  • Track power On/Off
  • System status
  • Programming track and POM
  • Running DCC locos with 14, 28 and 127 steps
  • MM support for addresses < 256
  • 28 Loco functions
  • Switch/Output commands
  • Timed switch commands for coils 1)
  • Sensor report evaluation
  • Switch report evaluation
  • Loco report evaluation
  • Watchdog to keep the connection alive after 30 seconds of idle time.
  • Programming RMBus
  • CAN Z21 10808 detector support



Factory default is which is also used if left empty.


Default is 21105 if left to zero.


:!: Only use this option in case locomotives are controlled by an external throttle which connects directly to the Z21/z21.
This option is needed for getting (speed, direction and function) info events from the Command Station of manually2) controlled locos to synchronize Rocrail clients.
Without this option the subscription on loco info is done individually for each loco after a speed or function command is send from Rocrail.

Report absent

If this option is activated, it will be reported if a loco ID is no longer recognized by a RailCom detector.  

Check Hostname

:!: Disable this option, and use the static Z21 IP address, if no sensor events are coming in. :!:

Use this option only if the Z21 the static IP address has been assigned a hostname.
In all other cases this option should be deactivated.
Note: For Network experts only!

Booster events

This option must be activated, if Booster events should be received from the the z21 controller.

LocoNet detectors

This option should only be activated if RailCom detectors are connected to the LocoNet bus of the z21 controller.
It activates OPC_MULTI_SENSE events. For more information see capital 9.5 LAN_LOCONET_DETECTOR in the Z21 Protocol Specs.
Note: Leave this option disabled in case no RailCom detectors are connected.


Check if the event is originated by the multiMAUS to signal Rocrail that it is a field event.

Program FB

z21-10787.jpg Program a Roco 10787 sensor module.

  1. Read the 10787 manual.
  2. Make sure only one sensor module is connected to the RMBus.
  3. Fill in the wanted address and push the "Program FB" button.
  4. :!: Program address zero after the sensor module has acknowledged.

Switch time

Default output activation time for switches.
This value is only used in case the Switch time for a individual turnout is zero.
Note: The output of the switch will only be reset after this time in case its activated.



Bus Network Z21 Firmware
0 DCC 1.0
1 Loconet 1.2

Switches, outputs and signals do only use the address field.
:!: If both address and port are set > 0 the addressing will be recalculated back to FADA. This is not recommended. (2.1.1577+)


Tip: Use the Sensor Monitor to find the right address.

Node ID Network Z21 Firmware Remark
0 R-Bus 1.0
1 LocoNet 1.2 LocoIO, DR5088RC(Feedback), DR5088RC(Block)
3 CAN 1.29 Roco Z21 CAN Detector

Flat addressing

Module 1 → Address range 1-8
Module 2 → Address range 9-16

Special Feature

In the default setting of the z21 / Z21 there is an address offset of +4 between Multimaus and Rocrail. This means that in Rocrail the addresses 1-4 can not be used. If e.g. address 1 of the multimouse is to be used in Rocrail address 5. But there is an elegant way to eliminate this shift. To do this, connect the z21 to the computer via the z21-maintenance-tool, activate the option "DCC-switch address shift +4" resp. "DCC tournout-addressing according to RCN-213" on the "Settings" tab and then confirm with "Write". Then the addresses from 1 can also be used in Rocrail. Addressing is done exclusively according to FADA (Flat addressing).

Power Manager

To add the Z21 to the Power Manger:

The address is fixed to 21, Interface ID is optional.

CAN Detector

Disable all emulation with the Z21 Maintenance Tool to prevent unwanted events:

Trouble Shooting


eth-switch.jpg The Z21 cannot access the LAN when connected to an 'old' Ethernet HUB.
The easiest way to get connected is to add a small Desktop Ethernet Switch between the 'old' HUB and the Z21. (Small Switches are available for less then €10.)

:!: "Set track power, by start of Z21, to STOP position".!


The z21start has a restricted network interface which does not accept commands from Rocrail or other software.
To use the z21start with Rocrail an Unlock-Code (10818) or an complete z21 WLAN Package (10814) must be installed.

Commands for the same address are rejected in case the timer did not yet elapsed.
External throttle
roco/roco-z21-en.txt · Last modified: 2024/05/06 14:09 by rjversluis