Quote from kme on November 25, 2011, 15:17
The UART pins are the RS-232 connector (RX, TX and power only).
Serial, RS232-style may be better than calling it "RS232" which has very specific definitions which I don't believe the R-PI will conform with.
The UART pins will be 0V/3V3 and likely be idle high signalling which is incompatible with direct connection to a PC COM port and USB-to-RS232 cables, and connecting them together directlty may even damage the R-Pi SoC.
An inverter and level-shifting will be required ( usually a MAX232 family chip ) to turn UART signals into RS232 signals, but some USB-to-serial cables and modules will be compatible with the UART signals.
The UART pins will also be able to connect to other R-Pi and micros directly ( 3V3 and probably 5V with simple single resistor current limiting ).
Quote from albertfrutos on November 25, 2011, 15:49
I hope more documentation will be provided when the device is launched, including how to connect the COM/RS232 to the board (welding, I suppose) and how to connect it to the computer. I think a full tutorial would be so useful for the newbies
For most people wanting to use RS232 with an R-Pi a USB-to-RS232 cable will be what's best to use. Simply plug the USB into the R-Pi and connect the 9-way D to the RS232 device.