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PRODUCT SPOTLIGHT - COBALT Ad 2fx Stall-Current Accessory Decoder

John Chandler

JOHN CHANDLER reviews this new Accessory Decoder from DCC Concepts.

DCC Concepts DCD-AD2fx  COBALT ip Stall-Current Accessory Decoder (2 Way)


Our Editor approached me to see if I could provide a review of our Antipodean supplier's, DCC Concepts, products; he suggested the Cobalt-Type decoder, DCD-AD2fx, capable of controlling two Cobalt DCP-CB1iP stall-current point motors. I agreed and assembled a suitable test bed!

Equipment used


Having read the manuals for both the DCP-CB1iP and the DCD-AD2fx, I connected them as instructed, i.e. DCP-CB1iP DC in to one set of the DCD-AD2fx outputs (DCD-AD2fx can handle two DCP-CB1iPs!)

I then connected the two central connectors of the DCD-AD2fx to my DCC01 Prodigy controller's Main Track connections.

With the DCC01 connected to my laptop via a trusty DCC55 computer interface, I was now set to test the decoder.


The decoder can respond to its controller in four different ways:

1. it can be programmed for its local DCC address.

2. it can respond to commands issued to it.

3. it can be instructed to reverse the operation of the DCP-CB1iP.

4. it can be instructed to self-centre to assist in installation with the point it is controlling.

Okay, so we need to give the decoder an unique address in order to communicate with it. I followed the instructions and put the relevant switch to its 'SET' position. One now needs to operate an accessory for the decoder to learn its new address. Be aware that addresses 197, 198 and 199 are reserved for special functions, as we shall find later.

Using the standard Gaugemaster / MRC software, I selected the 'Acc Control A' field and keyed address 125 before clicking the F1 and F2 buttons beside it on the screen to send some commands to the device. I then set the DCD-AD2fx's switch to 'RUN' and, using the aforementioned software, changed the DCP-CB1iP from one throw to the other several times. Neither the DCP-CB1iP nor the DCD-AD2fx seemed to experience any problems in this process.

Next, I put the switch to 'SET' and, using the 'Acc Control B' field, keyed address 197, as per the manual, before clicking the adjacent F1 key. Resetting the DCD-AD2fx's switch to 'RUN' and returning to the 'Acc Control A' control, clicking on the adjacent F1 and F2 buttons caused the DCP-CB1iP to respond in the opposite manner to the previous test. As suggested by the manual, the operation of the motor had been reversed; simplicity itself!

Terminals are provided for the connection of LEDs to indicate the point setting. Due to the nature of my test rig, these were not tested.

Another feature of the DCD-AD2fx is that it can be operated manually. The connector strip has three terminals identified as 'PB'. By wiring a switch, such as a GM510 or the DCP-CMS range (which includes suitable LEDs!), between these terminals, the point can be operated manually. This was tested and proved reliable.


Both the DCP-CB1iP and the DCD-AD2fx performed well under test, and the combination worked first time out of its packaging.


Given the way in which DCC Concepts have developed in recent years, I believe that this combination of DCD-AD2fx and DCP-CB1iP method of point control works well and reliably. Using the simple switch provided on the on the DCD-AD2fx circuit board, it is also very simple to program.

Regrettably, features such as the LED outputs and feedback control have not been tested for this review. Feedback control will only function with some brands of DCC system; with Gaugemaster DCC Controlers not currently supporting.


I should make you aware that DCC Concepts have several other similar products for 1, 2, 4 and 8 channel slow action and solenoid point operation.

John is currently preparing an article about a recent in-cab trip through Switzerland, stay tuned...

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