Network cable pinout wiring

[cbretana]

When creating my own Skyview Network cable, I thought I should connect pin1 to pin1 , pin2 to pin2, etc., all the way to pin9 connected to pin9. But when you look at the end of the female DB-9 connectors on a network cable that shipped with my Dynon HDX system, and do a continuity check on them, assuming you are looking at the end of the connector from the side that would plug into the HDX display, or into the network hub, with the row of five holes on top of the row of four holes, I would have expected that that would mean the wires are connected like this:

However, when I built one that way and tried it to connect my AHARS to the network hub, it failed. So I tried several of network cables that shipped with my HDX originally and they all worked. Confused, I eventually got out the circuit tester, and examined the ones that were working, and they are actually wired like this:

Funny thing is that the wires connecting the hub to the HDX display, and all the other components (COM Panel, EMS, and Autopilot Panel) are also wired like the bottom picture. So which is correct? How are these network cables supposed to be wired? and what is going on here?
If the one wire that I have between the hub and the HDX display was wired like the second picture, would that explain why everything was working?

 

[John Bright]

I'm guessing I'm misinterpreting your words and images.

You are attaching a D9Female to each end of the wires. Does each wire go to the same pin number as molded into each D9F?

The image below has been edited to match my next post.

Have you respected the twisted pairs described in the install manual? Search for "SkyView Network Pinout (SV-NET-XXXX)".

BTW, DB is 25 pins. I leave out the A, B, C, D, E because it's redundant with the 15, 25, 37, 50, 9.

 

[cbretana]

Your image shows pin 1 as being on right side of top row (row with 5 pins), so it is looking from the back, where you insert the pins, right?
Anyway, I now have a tentative hypothesis about what is happening. I think when I wired the cable coming from the EMS, three years ago, I miswired it and connected pin1 to pin5, p2 to p4, p3 to p3, p4 to p2, p5 to p1, p6 to p9, p7 to p8, p8 to p7, & p9 to p6. I must have had left & right reversed in my head when I built these cables.
So, that wire was connected to the hub, so it made the hub backwards - so for the EMS data to get to the correct pins on the D9 connector on the back of the HDX display, I had to wire the pins the same screwed up way on the wire from the hub to the display, (which i verified with a circuit tester). So, then all wires going into the hub had to also reverse the pins on each row because they were being reversed between the hub and the display.

Two years ago, when i installed my autopilot, I had a problem getting the system to recognize both servos, which until now, neither Dynon nor I have been able to diagnose. Because there was only one open network port left on the HDX, I put one servo on the hub and one on the the HDX. No matter which one was on the HDX, the one on the hub would not be detected, but the one on the HDX was. Eventually, I ended up splicing both servos into one D9F, and connected both of them to the remaing port on the HDX. That worked. But the fact that the cable from the hub to the HDX was reversed would explain that. I have checked the other cable going into the hub, (from SV-COM-PANEL), and it is also miswired in the same way.

My current problem arose because I also had the AHARS connected to the hub, but lost that cable, so I had to build a new one, but I built it the right way, but of course it failed, which makes sense since the wire from the hub to the HDX is reversed.

So I am pretty sure (99.9%), that i just need to examine the wire from the EMS, and if it is also miswired, fix it and rebuild the other three wires properly.
This might also explain the intermittent "data pair error on wires 4 & 8" I have been getting for some time.

 

[John Bright]

To avoid confusions as to what is back, front, rear, I like photos. Hope this one tells the story... a D9F on a cable with backshell in place.

I assume connector manufacturers get it right in the molds and reference that.

I look at the numbers rather than trying to figure out what is back, front, rear, pin insertion view, or whatever. I have seen incorrect depictions in install manuals, or either their words and my interpretation don't match. Pin insertion view... what is that?... looking where the technician assembles the pins into the connector?... looking where the user inserts the pins into the sockets?... I don't know. Similar confusion for me with front, back, rear.

 

[cbretana]

Yes! That may have contributed to my confusion when I originally built the network wires. In hindsight, for a network connection wire, front, back, insertion side, numbers, none of that really matters. What matters is that all the wires are in the same hole on both ends, (which in my confusion I failed to do).
.... and because I had done this on both the wires going into the hub, and the wire from hub to the HDX display, it was kinda like looking at something reflected in two mirrors. The image ends up reversed twice, back to its original, (correct) orientation.

 

[Dynon]

Just to clarify - SkyView Network connections are passthrough. Pin 1:1, 2:2:, etc etc

 

[cbretana]

Yes, that simple rule would have saved me much confusion, but I relied on left-right interpretation of pictures labeled "View from the back", and ended up reversing things. and to make the confusion worse, since I used reversed cables from components to hub, AND from HUB to HDX, I was reversing the pins twice, which effectively made the end result correct.
This is why everything was working until I added Autopilot, with properly wired connectors. Then only the servo connected to the HDX display worked, and whichever on I connected to the HUB failed.