Can trrs be used for audio?
Any connector can be used to pass audio. The key is the correct wiring and signal level. The TRRS connector on Apple devices is a combination headphone and microphone jack.
In a simple enough Answer the biggest, main idea difference between TRS and TRRS is the microphone. Usually TRRS will have a microphone and thus will have an extra ring around the bottom. Old Ipod headphones will have just the two white bands dividing the jack into three metal peices. These are TRS. iPhone headphones with the mic will have three white bands separating the jack into four metal pieces. this is TRRS