The unpopulated pin header SJ1 provides a 3.3 V serial port. See photo for pinout.
Serial connection parameters: 115200, 8N1
USB Mod v1
Atheros AR9330 rev 1
In v1 USB can be added with a MOD.
In v2 USB is present but no pinouts are available on PCB to solder USB socket.
For the v1 USB mod you need to solder wires to the following resistors: R100 (Pin 73) and R101 (Pin 74).
The side that is soldered is facing the LED'S. The side facing the RJ45 jack is ground.
I recommend using a thin gauge wire so as not to detach the resistors.
You can solder directly to the CPU but i recommend you solder directly to the back of the above resistors as this is easier. (Please remember to orientate your board correctly.)
A 5 Volt regulator is also needed to power the USB port.(You can add a filter capacitor.)
You will not need to add any additional resistors.
I do not recommend using the USB port with the PoE unless you upgrade the power supply.
The way the USB port has been powered will only work when the power supply is plugged directly into the access point.