10South bridge controller. Referred to as the Intel I/O Controller Hub 2 (ICH2) of the Intel 845D chipset, this controller provides the I/O subsystem that allows access to the rest of the system. The ICH2 integrates I/O functions such as system bus interface, Ultra ATA/100, Low Pin Count (LPC) interface, Universal Serial Bus (USB) 1.1 interface, PCI interface, and CNR interface.

11ASUS ASIC. This chip performs multiple system functions that include hardware and system voltage monitoring, power management routing, among others.

12AGP warning LED. Serving as a smart burn-out protection for the motherboard, this red LED lights up if you plug in any 3.3V AGP card into the AGP slot. When this LED is lit, there is no way you can turn on the system power even if you press the power button.

13Onboard LED. This onboard LED lights up if there is a standby power on the motherboard. This LED acts as a reminder to turn off the system power before plugging or unplugging devices.

14CNR slot. This slot is specifically designed for the Communications and Networking Riser (CNR) card. The CNR supports V.90 analog modem, HPNA, USB Hub, and the 10BASE-T/100BASE-T Ethernet networking.

15Audio CODEC. This AC ‘97 audio codec provides stereo analog I/O on the motherboard and peripheral devices to deliver high quality audio to PC-connected speakers, headphones, and microphones. The codec includes analog-to-digital and digital-to- analog sample rate converters, as power amplifiers and programmable gain blocks. (on audio models only)

16PCI slots. These three 32-bit PCI 2.2 expansion slots support bus master PCI cards like SCSI or LAN cards with 133MB/s maximum throughput.

17LAN controller. This RealTek 8100 PCI LAN controller fully supports 100BASE-TX Ethernet networking. (on LAN models only)

18AGP slot. This Accelerated Graphics Port (AGP) slot supports 1.5V AGP4X mode graphics cards for 3D graphical applications.

19Microphone jack. This Mic (pink) jack connects a microphone. (on audio models only)

ASUS P4B266-M motherboard user guide

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