TRS is the abbreviation for “Tip Ring Sleeve.” This is the accurate term for 1/4″ (or 1/8″) balanced connectors. A TRS plug can be found at the end of most headphone cords if you want to know what one looks like. It looks like a standard 1/4″ plug with an extra “ring” on its shaft. Thus the three sections of the shaft are called the Tip, Ring, and Sleeve. TRS connectors are used wherever you need to have two conductors plus a ground (shield) in one plug. A common use is to connect balanced equipment. A useful cable is the Hosa (CSR103) CSR103.
XLR is the trademarked name for circular 3-pin connectors developed by Cannon (later bought by ITT). XLR has since evolved into a generic industry term, and many manufacturers now make this style connector, in which there are positive, negative, and ground connections. In audio, XLR connectors are normally used for transmitting balanced mic and line level signals to mixers or audio to speakers. Monster Cable’s (P500M20) P500M20 is a good example of an XLR cable.
TS is the abbreviation for Tip Sleeve and refers to a specific type of 1/4″ connector that is set up for two-conductor unbalanced operation. An insulator separates the tip and sleeve. The tip is generally considered the “hot,” or the carrier of the signal, while the sleeve is where the ground or shield is connected. TS cables are best known as guitar or line-level instrument cables, such as this one from (099-1210-090) Fender.
RCA connectors are the common name for phono connectors like the ones used to connect most consumer stereo equipment. These were so associated with the RCA Corporation in the early 1900s that they became known as the RCA connector. Some mixers have tape or CD inputs and outputs with RCA connectors. Hosa’s (CRA206) CRA206 is an example.
A Banana Plug is an electrical connector designed to join audio wires such as speaker wires to the binding posts on the back of many power amplifiers, or to special jacks called, of course, banana jacks. A common configuration of banana plugs is to have two of them molded together and spaced 3/4 of an inch apart, which is also the spacing of the binding post receptacles on the back of power amps. Here’s an example of a Hosa cable (SKJ475BN) with a TS Plug on one end and a double banana plug on the other.