TRS means Tip-Ring-Sleeve. In a normal unbalanced configureation as for headphones the tip is the left channel, the ring is the right channel and the sleeve is the ground.
To have a true balanced connection you must have 3 connections for each in/output as in an XLR connector. Pin 1 is the ground, pin 2 the positive, pin 3 the negative.
You can unbalance an XLR to an unbalanced connector by jumping pin 1 to pin 3 in the xlr but you will lose about 6db in level. Any connector with only 2 connections (tip-sleeve) is an unbalanced connection.
Eric