EFIS Serial Ground Connections

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For the ARINC module, Drawing 53620WD (ARINC Adapter dwg) states 'Serial #1 GND Pin - NOT REQUIRED' (G430W connection). EFIS dwg 53600 shows this ground connected.....which is correct? How about for Serial 2 and Serial 3....are grounds required for those?

And for the Magnetometer? Is a ground required for this?

Thanks