Digital I/O Ports - Section C on said diagram, used for some sensors
2 Axis Accelerometer - Measures accelerations on 2 axies, likely both lateral dimensions. The VEX Accelerometer is 3 axis
12C Smart Ports - You probably mean I²C (Inter-Integrated Circuits), again a communication port. Used for Integrated Motor Encoders, but more (processor?) focused, because IMEs have a processor in them.
High-Resolution Analogue Ports (12 bit) - More Serial Ports on the Cortex, used for some sensors
Config hole - I actually don’t know what this is
PWM - The metric for the power of a motor, a signed 8-bit integer from -127 to 127
Control Signal - A pulse of electricity used to indicated some sort of command over a communication protocol
Rx1 & Rx2 - More Communication Ports. You probably ment Rx and Tx.
To add to that: PWM stands for “pulse width modulation.” That will allow you to look it up more easily if you want to understand the details behind it.
These are not serial ports. There are 8 ports (plug ins) on the VEX Cortex labeled “Analog”. Each port can be measured by an A/D converter, which is a sensitive voltmeter. The notation “12 bit” means the numbers reported by the A/D converter have that level of accuracy. A 12 bit number can range from 0 to 4096. Since the full range of the analog input (that is, the full range the internal “voltmeter” can measure) is 0 volts to 5 volts, you divide 5 into 4096 parts to determine what a single bit change means in an analog input. When you do, you find that a single bit change in an anolog reading corresponds to a change of 0.00122 volts.
Sensors of various kinds can be hooked to the analog ports.
This is a small reset switch recessed into the end of the Cortex. The hole through which the switch is accessed is labeled “Config.” Pressing that switch with a ball point pen or a toothpick during powerup will put the Cortex back into a known default state from which it can be reconfigured. You really shouldn’t need to do this very often; maybe never.