It depends on the application. A 1/4" TRS (tip, ring, sleeve) connector can be used to carry either BALANCED mono signal, or UNBALANCED stereo signal.

Recall that a balanced signal requires three conductors: signal+, signal-, and common. Stereo on a single cable also requires three conductors: left, right, and common.

So, a TRS can be either carry a balanced signal, or a stereo signal, but not both.

The type of signal is determined by what the input/output jacks you are plugging into expect, not the cable itself.

You've gotten the basic answer already, but the flip-side is that TRS/XLR aren't necessarily always balanced. You probably won't run into unbalanced TRS/XLR in any decent store bought cable, but it's always good to have a cable tester (or multi-meter) to confirm.

they're rings ;) you can make them anything depending on your connector. 1/4" TRS is normally mono (single channel) - balanced, like an XLR.

Read up here: http://en.wikipedia.org/wiki/TRS_connector#Tip.2Fring.2Fsleeve_terminology