A sound card jack is one of the interface types on a sound card. For most cards, they are the primary method of sending signals to, or receiving signals from, the sound card. On a sound card, the ‘jack’ referred to is typically a Tip/Ring/Sleeve (TRS) connector, more commonly called a stereo plug, but any connector on a standard sound card may be called a jack. A sound card jack may be used to output sound or input sound.
During the late 80s and through the 90s, soundcards replaced the personal computer (PC) speaker as the primary method of making sound. While the early cards were very rudimentary, within 10 years, the cards had advanced significantly. In the beginning, there were few connectors on a standard card, but by the turn of the century, the number of ‘basic’ connections had grown significantly.
In the mid to late 90s, sound cards began to change. They shifted from stereo plugs to optical connections and Radio Corporation of America (RCA) jacks. In addition, motherboard manufacturers began to build simple soundcards directly into their products. As the technology improved, on-board sound cards have become a standard part of most motherboards. These cards are often nearly as powerful as their expansion board equivalents with many similar features.
Any sound card, regardless of whether it is built-in or not, has jacks that the card uses to take in or send out information to external sources. The original TRS jacks are still common, but now they share space with several other types of connectors. Many sound cards have an optical connection, although it may be on a secondary board with on-board sound. In addition, some sound cards use standard RCA plugs or high-definition sound jacks to allow the card to plug directly into a television or digital video disk (DVD) player.
Most cards use a color-coded sound card jack system. Lime green jacks are standard headphone or front speakers, making them the most common jacks. A black sound card jack is for center speakers, and orange is for a rear speaker or a subwoofer. Brown jacks are for special speakers that run sound between them to give the illusion of moving sounds. These are the primary speaker connections.
In addition to the speaker jacks, there are several other sound card jacks in a standard set. A light blue sound card jack is the line channel for attaching other audio equipment. Pink jacks are specifically for microphones. Gray jacks are used for musical instrument digital interface (MIDI) connections, and gold are game ports.