JMRI® connects to...
Controller Area Networks (CAN)
Supported Hardware
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Hardware Support: CAN: Controller Area Networks

There's an emerging trend to develop model-railroad control systems that are based on standard CAN technology. JMRI provides support for the development and use of these. Two systems are described below.

CAN Implementations


OpenLCB logo

OpenLCB is a group of hobbyists and manufacturers who have come together to produce a future-oriented layout control bus, also called OpenLCB.
JMRI includes basic support for OpenLCB, and more is being developed along with OpenLCB itself.

NMRA logo

The NMRA has decided to adopt OpenLCB and standardize it as Layout Command Control (LCC, formerly NMRAnet).


Originally named CBUS by co-founder Gil Fuchs, CBUS is an 'open' protocol for Model Railway use. The protocol and other useful information is hosted on the MERG public website (see further support links). CBUS is not owned or controlled by MERG but the co-founders Gil Fuchs and Mike Bolton are active members. MERG members are able to purchase a range of CBUS kits.

CBUS adopted the Gridconnect scheme but with a slight modification.
The header is always HEX bytes and maps directly to the PIC CAN registers, left justified.

JMRI CBUS support is available for linking JMRI with CBUS, aimed at users.
Extensive details of the CBUS protocol are available to developers, see the CBUS Wiki hosted on the MERG public website.

There are many MERG module kits available to help running a layout.
Modules can be thought of as

The 3,000+ MERG members are encouraged to to build and design their own modules, and with MERG being over 50 years old, there is a strong peer review process behind CBUS.
Module firmware updates can be performed over the CBUS network

JMRI includes support for CBUS events, also DCC over CBUS via a CANCMD kit (a fully featured DCC Command Station, mini booster and track programmer). This interfaces to JMRI and / or MERG handheld controllers over a CBUS network.

CBUS events are sent as one-to-many, enabling multiple modules to listen and change status on 1 single event. eg.

JMRI can send and receive events for any module node and any module event.

Supported Hardware

Computer Interfaces

Various CAN-USB adapters are available:

TCH Technology
TCH Technology CAN/USB provides a high-speed connection for model railroad use (site not accessible as of 2019)
grid connect
LAWICEL AB CANUSB and CAN232 adapters.
CANUSB4 A CBUS to USB interface, available in kit form to MERG members.
CANISB A galvanically isolated CBUS to USB interface.
USB-LCC A galvanically isolated LCC to USB interface.
CANable An Open-Source USB to CAN Adapter, these use the CAN via Lawicell CANUSB System Connection.

Raspberry Pi Adapters

PI-LCC Raspberry Pi adapter for OpenLCB/LCC (New product).

Other CAN Hardware Interfaces

The CAN-GC1e Ethernet module can connect to JMRI via MERG Network Interface
The CANPICAP enables direct CBUS connection to a Raspberry Pi via its 40 pin I/O connector, available in kit form to MERG members.
The CANPiWi is based on the Raspberry Pi Zero W, and is an interface between Engine Driver / WiThrottle and CBUS.
SPROG DCC Pi-SPROG 3 Plus CBUS DCC Command Station for direct attachment to a Raspberry-Pi via its 40-pin I/O connector.
SPROG DCC SPROG 3 Plus CBUS DCC Command Station with integrated USB interface.


JMRI can provide the usual Sensor and Turnout features, once configured for OpenLCB or CBUS "Events".

Example System Naming:

Sensor Turnout Light
( Event 18 Active / Inactive )
( Node 2 Event 18 Thrown / Closed )
( Event 18 On / Off )

JMRI can connect to CAN networks in several ways:


To use any of the above adapters, select the appropriate device/connection type in the JMRI Preferences. If using a GridConnect or Lawicel device, be sure to set the appropriate baud rate under Advanced Preferences.
The TCH Technology adapter does this automatically, so no setting is required.

To connect to a CANUSB4, select "MERG" as system manufacturer, then "CAN via MERG CAN-RS or CAN-USB" as system connection.

TCP/IP Network

It's also possible to attach via a TCP/IP connection (EtherNet or WiFi). This can either go to another JMRI instance running e.g. an OpenLCB hub, directly to an IP-CAN adapter, or a CAN Server. To configure one of these, open the Connections tab in the JMRI Preferences.



CBUS Server is a Node.js program, licensed under MIT to allow multiple network connections to a MERG CANUSB4.




OpenLCB Help

CBUS Support

JMRI Scripting for CAN frames.

Third Party info


CBUS is a registered trade mark of Dr Michael Bolton