The CTC-Loco-Module-21mtc is being sold off. The successor is the CTC-Loco-Module-M3 .

The CTC-Loco-Module-21mtc is only useful for locos with Märklin’s 21mtc interface . Due to the standardized connector, this loco module can be installed without soldering. For older locos, there are various adapter boards with larger solder pads or cables available on the market.

Property Description
Optimized for Locs with Märklin 21mtc interface
Dimensions 30 x 15.5 mm
Processor Espressif ESP32
Input voltage approx. 9 V to 24 V DC or digital current or AC (with support capacitor)
Motor output 1x DC motor: continuous current 1.0 A, peak 2.8 A
Switching outputs 6x 500 mA LowSide (F0L, F0R, AUX1 to AUX4)
2x Digital (AUX5, AUX6)
Total current max. 2 A
Interfaces CTC-IR receiver, train bus (e.g. as I2C), 2x servo, 2x input
Passive online power TBD
Boot current 50 mA at 15 V

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In the overview "CTC-Loco-Modules " you will find further modules and links to installation instructions.

Pin assignment

Details on pin assignment and dimensions can be found in the RailCommunity Norm RCN-121 .

The image still shows the first version:Loco module 21mtc

Connection

Notes:

  • When selecting the input voltage, please remember that motors, lights, etc. connected to the CTC module must also be compatible with this voltage The train bus is not supported by the current firmware.
  • When soldering cables for the buffer capacitor, ensure that plugging the 21mtc connector is not obstructed.

To connect:

  • plug the CTC module onto the 22-pin 21mtc connector.
  • plug the optional CTC IR receiver into the 10-pin socket on the CTC module (red marking points toward the center of the board).

The assignment of lighting and AUX connections to switches in the app can be freely configured (Cfg.xml).

Additional connections

  • Under ExtOut-1 and ExtOut-2, two additional switching outputs with max. 500 mA are available.
  • Under Input-1 and Input-2, two digital inputs are available.

IR receiver

We supply you with a cable with a suitable 10-pin connector for the IR receiver. Installed in a Märklin loco BR 247 (#36292), it looks like this:

Loco module 21mtc in loco