There are two ways to do this: with "Output State" messages (only really used by CML products) and with "Turnout Feedback" messages (used also by other software including TrainController).

If you don't need to use other software, the easiest solution is to program the DAC20 output cells to generate “Output State, only when interrogated”. When the railway starts up, the command station interrogates accessory devices. The DAC20 will send "Output State" messages for each cell and and the DTM30 will be able to see the DAC20 positions and light its LEDs.

If you are already using Turnout Feedback switches and messages, you will have programmed the DAC20 inputs to generate Turnout Feedback messages. The inputs will be wired to microswitches of some kind on the point tiebars. The DTM30 cells need to be programmed to "uses turnout feedback".

It is also possible to use "Turnout Feedback" mesages but WITHOUT microswitches. The DAC20 can be programmed to generate "Turnout Feedback" messages every time the output changes. Select “Output State message" in this case.

You can also use the “Turnout Feedback” messages, which other software will be able to read. If you use those, then the DTM30 needs to be programmed to look for those messages by selecting “uses turnout feedback”