What is this type of jack with contacts and light emitting diode called (from schematic symbol)?
It's probably a Mini-TOSLINK port which combines 3.5 mmm electrical stereo and optical S/PDIF / TOSLINK in one connector.

Pins 6, 7 and 8 are related to the laser diode of the TOSLINK output.

Wikipedia says:


  Combined 3.5 mm jack and mini-TOSLINK sockets exist which can accept a 3.5 mm jack or a mini-TOSLINK plug; mini-TOSLINK plugs are made 0.5 mm longer than electrical jack plugs so that the latter are too short to touch and damage the LED of combined connectors. Many laptop computer and portable digital audio equipment models, such as the Google Chromecast Audio device[6][7] and Apple AirPort Express and iPod Hi-Fi, use these connectors that allow for the insertion of 3.5 mm electrical headphone output or microphone input or mini-TOSLINK digital output.


This is an adapter used to convert standard TOSLINK to Mini-TOSLINK. Note the typical 3.5mm jack form:



(Source: radioshack.com)