On the Yun there are two groups of holes, one a group of 4 and the other a group of 6. Does anyone know what they are connected to? The schematic mentions them, but is not very informative. I'm thinking a serial connector to the AR9xxx chip and JTAG.
Arduino Yun 5.0 v/13 w IEEE802.3af compliant PoE Module.
And that means...
Power-Over-Ethernet Module
sonnyyu:
Power-Over-Ethernet Module
Hi sonnyyu,
I am running a CAT5 cable out to my Yun in the greenhouse, and this might be a nice way to power the Yun. Do you happen to know any source for the poe module , I have seen Yuns sold with the module, but have not found the module itself.
Bjarne
AG9000-S 5.0 V ?
If I were you, I will be waiting official answer.
Digikey sell those module and instock.
AG9050S
Thanks.
JTAG_TDO A54 GPIO_7 is masked.
Answer for OP is no JTAG on Yun board.
sonnyyu:
Answer for OP is no JTAG on Yun board.
@sonnyyu: Are you sure that this is entirely correct? I think that you are referring to the pinout of the Linuino Atheros AR9331 (which also is supposed to support JTAG OCD http://www.openhacks.com/uploadsproductos/ar9331_datasheet.pdf ). So a JTAG connection to the Atheros would indeed not be possible for the setup on the Yun board.
However, I think that what would be possible on the Yun is a JTAG connection (and OCD) to the ATmega mcu. The connections to these look fine to me
So by using the analog outs + GND, 5V and RESET you should be able to make a JTAG connection to the yun for programming/debugging?
I thought OP ask JTAG for AR9xxx chip
mwalimu:
...
I'm thinking a serial connector to the AR9xxx chip and JTAG.
I guess 100% correct answer is no JTAG on Yun board for AR9xxx chip.
BTW, I do not know how Yun's ODM (An original design manufacturer) manage QC (Quality control ) on Yun board without JTAG, they might have magic method "Just Flip A Coin". 
My mistake, I have missed that detail in OP's post 
I was too much focused on how to make JTAG work at all on the yun.
But you have a very good point about the QC. That is exactly the problem I'm running into now, because, as I have just found out, although it is supposed to, the JTAG on the ATmega side doesn't work either! And since the ATmega32u4 doesn't support debugWire as far as I know, there is no way to debug either side of the bridge?!
I will start a new thread for this, with the stuff I have tried so far to make it work, because I really don't want to use println for the kind of projects I am working on. I hope that is not how the ODM does it 