Establishments primarily engaged in packaging, repackaging, and bottling of purchased chemical products, but not engaged in manufacturing chemicals and allied products, are classified in Wholesale or Retail Trade industries.
A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog audio signals. The phone connector was invented for use in telephone switchboards in the 19th century and is still widely used. The phone connector is cylindrical in shape, with a grooved tip to retain it. In its original audio configuration, it typically has two, three, four and, occasionally, five contacts. Three-contact versions are known as TRS
S/PDIF it s a port used to transmit audio signal by converting 1 and 0 to sound signal or sound signal to 1 and 0, it has tow common connector (RCA) for coxial cable and (TOSLINK) to fiber cable. it's what you said it is, an audio port. it's for digital audio.