Overview

Retaskable jacks, sometimes known as Universal Jacks, were introduced in the final 2.3 revision of the AC97 specification, and they are more fully supported under the Intel HD Audio specification.

The concept of retaskable jacks is actually a combination of four different but complementary technologies:

• Jack Detection or Jack Sense The capability to detect jack insertions, which is a requirement of both the Intel HD Audio specification and Windows Vista logo program

• Switchable Microphone Bias The capability to independently turn microphone bias off and on for each port

• Redirection The ability for a port to function as either an analog input or analog output

• Impedance Sensing The optional ability to sense the impedance of an analog device and to determine the class of device being used: e.g., microphone, headphone, or line-level input or output

• Analog Device Classification A somewhat imprecise method of determining what type of a device is at the other end of a cable plugged into the jack, according to the following classifications: microphone, headphone, and high-impedance line-level device, such as a powered speaker or a stereo receiver

Automatic jack retasking builds on these technologies to allow a system to detect automatically what is plugged into a jack and then automatically reconfigure the jack. While automatic jack retasking seems promising, you face considerable technical and usability challenges in getting it to work properly, especially in a manner that minimizes expensive customer support incidents.

Early expectations for jack retasking included the possibility of reducing cost and saving space...