What pin of the TX and RX port handles data? I am guessing the one closest to the TX label is data, the middle is +5, and the one closest to the edge of the Vex is a ground. Is this correct or am I confused?
You are correct. The TX and RX data pins are on the inside by the marking. The center pin is +5V and ground is the outside pin closest to the edge of the Vex Controller. This pattern is true for all the pins in the connector.
How would I read and write to the RX/TX ports on top of the vex (next to the 16 digital I/O ports) in MPLAB?
There is a workspace called VexUserCode_DDT.mcw in the Vex Starter Code zip file located on our Downloads page at http://www.vexlabs.com/vex-robotics-downloads.shtml. Look at our DDT files for examples. These pins are for the advanced user.
What are the TX are RX Analog/Digital ports for, and how does one use them?
The TX and RX is a TTL serial port to the micro-processor. These pins are for the advanced user and can be used for any TTL serial port application. See above post for “how to use them”.