What is the difference between TS, TRS and TRRS?

TS, TRS and TRRS are abbreviations for Tip/Sleeve, Tip/Ring/Sleeve and Tip/Ring/Ring/Sleeve.  These often refer to the amount of contacts on the end of an Auxiliary cable or Quarter Inch cable.  A TS cable is often thought of as mono, as it only has one contact and is only going to give one solid sound signal.  A TRS is often though of as stereo, as the addition of the ring gives us two contacts allowing us a left and right audio channel.  Finally, a TRRS cable is usually going to include both a left and right channel as well as a microphone channel.  These TRRS cable are often found at the end of headset or earbud sets that include an inline controller and allow You to speak using a small built in microphone.  The easiest way to identify the three of these is to count the number of black rings on the head of the cable.  One ring for TS, two for TRS and three for TRRS.