Southbridge

The SIS southbridge:

two SATA ports (for DVD drive and HDD)
6 USB2 ports (2 for front, 1 for rear/WiFi, 2 for memory unit ports, 1 for RF module)
100Mbit Ethernet MAC (SMC) (with BCM5241 PHY chip)
consumer IR port for remote control
audio output and XMA decoder DSP
NAND flash interface
'Front bus': two wire I2C like interface to RF module. Used for example to control LEDs around power button
SMBUS: available on J201, pins 7 & 8

There is a an on-board TPM security chip by Infineon. See http://www.extremetech.com/article2/0,1697,1853986,00.asp for details.