The SUSI interface allows the separation of decoder and sound module. In the meantime, there are tiny SUSI sound modules and even speakers with built-in SUSI sound module. This means that even with limited space, the chances are good of enjoying loco sound with CTC as well.
The SUSI3 interface can currently be retrofitted for all CTC loco modules (except CTC-Loco-Module-H0a). You only need a current firmware (at least 20230902) and the CTC app version 4.19 or newer.
The SUSI3 module must handle 3.3 volt signal levels (hence the "3" in SUSI3) and tolerate the track voltage as power supply. Uhlenbrock support has confirmed these specifications for the current IntelliSound 6 modules .
Since our previous CTC loco modules do not have a SUSI socket, a suitable adapter must be made for them. How to do this is documented below and in our loco conversions . If required, we will be happy to create a suitable adapter for you.
Original Sound
There are locos that use a SUSI3 module for sound right from the factory. In this case, you can control the motor and loco functions directly with CTC and still enjoy the original sound of your loco. This works, for example, with the PIKO’s Spur-G model of the BR50 .
Retrofitting Sound
If you do not care about the original sound or the loco to be converted to CTC did not have any sound at all, you can purchase a SUSI3 sound module and connect it to the CTC loco module.
The Märklin BR247, which has always accompanied us at our trade fairs, has now been equipped with SUSI3 sound. Details can be found in the conversion report of the BR247 .
SUSI3 Adapter for CTC Loco Modules
The four pins of the SUSI3-classic socket must be connected as follows:
- Plus (red) to VBB
- Ground (black) to GND
- Data (grey) via at least 470 Ohm resistor to a GPIO pin of the processor
- Clock (blue) via at least 470 Ohm resistor to a GPIO pin of the processor
Adapter for CTC-Loco-Module-21mtc
For the CTC-Loco-Module-21mtc:
- Clock (blue) is connected to "Input-1 (Pin 33)" on the additional socket and
- Data (grey) is connected to "Input-2 (Pin 32)" on the additional socket.
Additionally, we must connect Plus (red) to VBB and Ground (black) to GND:
- In the image, we did this directly at the solder pads of the 21mtc socket.
- Alternatively, the significantly larger solder pads on the other side of the CTC loco module, intended for the support capacitor, can be used.
Adapter for CTC-Loco-Module-PluX22
For the CTC-Loco-Module-PluX22:
- Clock (blue) is connected to "NFC TX (Pin 25)" on the additional socket and
- Data (grey) is connected to "NFC RX (Pin 23)" on the additional socket.
Additionally, Plus (red) must be connected to VBB and Ground (black) to GND:
- This can be done directly at the solder pads of the 21mtc socket, as with the 21mtc.
- Alternatively, the significantly larger solder pads of the CTC loco module, intended for the support capacitor, can be used.
Adapter for CTC-Loco-Module-G
For the CTC-Loco-Module-G, we use the connections intended for servos:
- Clock (blue) is connected to "Servo-2 PWM".
- Data (grey) is connected to "Servo-1 PWM".
Since the servo connections on the CTC module already have a 1 kOhm resistor, no separate resistor is needed here.
Plus (red) can be connected to VBB and Ground (black) to GND via the socket intended for the 5 volt voltage regulator.