Talking 4500 boxes here.

I have the ARINC 429 cables made up. In doing my final cross checking I discovered that I had configured the ARINC Serial #1 GRD wrongly.
I had connected this to pin 2 of the EFIS Expansion DB9 connector but the 7.4 manual drawing on page 126 shows it connecting to pin 5 of the EFIS Expansion.

I couldn't understand why I had made this mistake so went searching the manual again.

I found that the EFIS Expansion Connector Table on page 101 shows the Serial #4 GRD as being pin 2. So that's where I got the specification from for my wiring
That table simply labels EFIS Expansion pin 5 as "GROUND".

Which EFIS Expansion Connector pin should be used for the ARINC Serial GRD? Pin 2 or pin 5? Or will either work?

It would be good to remove the document contradiction at the next release of the manual.

Thanks,
Steve Hutt