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NDC-4 Inputs not working

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If only a single input on the NDC-4 seems to be receiving data, please check that your NDC-4 is not in autoswitch mode. When in this mode, only data from input 1 will be used. This function is designed for when using more than one source of the same type of data, like a GPS for example. When the primary source on input 1 fails, it will switch to input 2.

To check which mode your NDC-4 is in, you will need to connect it to a PC and use our freely available NDC Control Centre.

You can connect your NDC-4 to a PC using the USBKit lead that plugs in to the PCB, or you can use a serial connection to “OPTO IN 0” and “ISO OUT 0”.  Full instructions for how to connect the NDC-4 to a PC can be found in this article.

DO NOT USE THE USBKIT LEAD WHILE THE NDC-4 IS CONNECTED TO AN EXTERNAL BATTERY SOURCE. Doing so will create a ground loop and damage the USB chip. This damage is not covered by the guarantee.

When a successful connection is made, click ‘Get from Hardware’. Once loaded, check the button on the right that will either say ‘Change to Combiner’ or ‘Change to Autoswitch’.

If it says ‘Change to Combiner’, your NDC-4 is in Autoswitch mode. Click this button to change it to a combiner.

If it says ‘Change to Autoswitch’ and you are still experiencing issues with your inputs, please browse some of the other NDC-4 articles in this Support Centre or contact our support team using the ‘Submit a Ticket’ option.

For more information on NMEA 0183 and how it works, please download our free guide to NMEA 0183 networking here: https://actisense.com/everything-to-know-about-nmea-0183-guide/