It is also known as audio card. This card deals with all applications which play songs, edit videos or audio, presentation software, games equipment and any program which plays audio. Nowadays, most computers come with integrated sound card, but for more advanced sound features you can install additional sound card. Sound cards came in two forms: internal and external. Internal cards are installed in the motherboard and external cards can be connected via a USB port. Audio cards convert the digital sound data into the analogue format, which is then forwarded to an external device capable of playing sound such as headphones or a speaker. This is known as Digital-to-Analogue Converter (DAC) adapter. They can also perform conversion in the reverse direction; they take analogue input from microphones and convert it into digital to save it on the computer. The features available on a sound card depends on the price of the sound card. A typical sound card has three or more small, round, 1/8″ jacks to connect the PC to microphones, headphones, and speakers. On advanced sound card, these are a possibility that a SPDIF in and out port is available. This port is used to send and receive digital data. It is not good as a HDMI port but better than composite AV cable.