When transistors are in the SMT6, or UMT6 package and are either PNP X2, or NPN X2, and have the same pin functions even when the part is rotated 180 degrees, the part is taped with T110 or TN respectively. This package pinout is sometimes called symmetrical pin-out and the taping is referred to being non-directional. (The whole reel has pin 1 either at the sprocket feed holes, or pin 1 is opposite side as feed holes.) Part number example: UMT1NTN.
Likewise, for Diodes that are in SMD6, or UMD6 packages that have the same function even when the part is rotated 180 degrees, these parts have T110, or TN taping respectively. The taping is referred to being "No feed direction". The Diode section of the Short form catalog will show the needed tape code alongside the Diode P/N.
These so-called symmetrical parts can only be ordered in Non-directional/No feed direction taping.