This driver supports all ALC series audio chipsets from ALC101 up to ALC861. It is used as onboard sound on many Realtek motherboards.
Chips covered include ALC101/201/202/203/250/650/653/655/658/861
The ALC203 is a 20-bit DAC and 18-bit ADC full duplex Realtec AC97 audio Driver Rev 2.3 compatible stereo audio CODEC designed for PC multimedia systems, including host/soft audio and AMR/CNR based designs.
The ALC250 incorporates proprietary converter technology to achieve a high SNR (100 dB), sensing logics for device reporting, and a Universal Audio Jack for improved user experience. The ALC250 AC97 CODEC supports multiple CODEC extensions with independent variable sampling rates and built-in 3D effects. Two pairs of stereo outputs with independent volume controls, a mono output, and multiple stereo and mono inputs, along with flexible mixing, gain, Realtek AC97 Audio Driver Download and mute functions provide a complete integrated audio solution for PCs.
The circuitry of the ALC202 CODEC operates from a 3.3V digital power and 5V analog power supply with EAPD (External Amplifier Power Down) control for use in notebook and PC applications. The ALC250 integrates a 50mW/20Ohm headset audio amplifier into the CODEC, saving BOM costs. It also supports the SPDIF out function (complies with AC'97 Rev 2.3) that offers Realtek AC97 Audio Driver Download easy connection of PCs to consumer electronic products, such as AC3 decoders/speakers and mini disk devices.
The ALC101 CODEC supports host/soft audio from Intel ICHx chipsets as well as audio controller based VIA/SIS/ALI/AMD/nVIDIA/ ATI chipsets. Bundled Windows series drivers (Windows 98/ME/NT/2000/XP), EAX/ Direct Sound 3D/ I3DL2/ A3D compatible sound effect utilities (supporting Karaoke, 26 types of environment sound emulation, 10-band software equalizer), HRTF 3D positional audio and Sensaura3DPA (optional) provide an excellent entertainment package and game experience for PC users. An integrated 14.318MHz -> 24.576MHz PLL circuit generates the required clock and eliminates the need for an external crystal. In addition, the ALC250 is embedded with a 7-band digital hardware equalizer to optimize speaker frequency response for mobile PCs.
l C3DX is the registered trademark of Realtek AC97 Audio Driver Download.

Description	Version	Update Time	File Size	Download
				Site 1	Site 2	Site 3
README	A3.89	2006/06/07	31k	Go	Go	Go
Windows 98Gold/98se/Me/2000/XP/2003(32/64 bits) for Driver only. For Windows 98 SE, DirectX(R)8 is required to enable advanced features. (ZIP file)	A3.89	2006/06/07	17836k	Go	Go	Go

With high speed PCI V2.1 bus controller and legacy audio SB16 DSPemulator,CMI8738 is designed for PC add-in cards and all-in-one motherboards. No external CODEC is needed in CMI8738: CMI-8738 supports the legacy audio SB16, FM emulator/DLS wavetable music synthesis, and HRTF 3D positional audio functions. Above all CMI8738 supports Realtek AC97 Audio Driver PCtel HSP56 (1789) interface. Being compatible with A3D and DirectSound 3D, CMI8738 meets PC98 requirements, and supports professional digital audio interface such as 24-bit SPDIF IN (0.5V ~ 5V)and OUT(44.1K and 48K format).
The digital interface circuitry of the ALC101 CODEC operates from a 5V/3.3V power supply with EAPD (External Amplifier Power Down) control for use in notebook and PC applications. The ALC101 integrates a 50mW/20ohm headset audio amplifier into the CODEC, saving BOM costs. The ALC101 CODEC supports host/soft audio from Intel 810/815/820/845 chipsets as well as Realtek AC97 Audio Driver audio controller based VIA/SIS/ALI chipsets.
Realtek licensed HRTF 3D library from Central Research Lab (CRL), U.K, who provides one of the world's best Realtek AC97 Audio Driver HRTF libraries (CRL also licensed its audio technology to YAMAHA, ESS, and other well-known sound chip makers).

HRTF 3D Positional 3D (Realtek 3D)
Only this sound processing technology can be called real 3D manifestation, as 3D usually refers to the three dimensions of X, Y and Z. This technology allows people to pin-point the location of sound in the real world (up/down, left/right, front/back)using only two speakers or a pair of headphones. This technology also supports interactive 3D applications to get a real-time placement of sounds via Realtek AC97 Audio Driver API (application programming interface) such as Microsoft DirectSound3DTM. We can also use this technology to simulate Multi-speaker Surround with two physical speakers to deliver five virtual" speakers in the air, surrounding the listener and creating home theater sound environment. This is the most economical and the easiest solution to people who would like to get high performance Realtek AC97 Audio Driver Downloadsurround sound but dont want to spend money in adding extra speakers.