In Star Trek: The Original Series, what device records a person's physical pattern for teleportation?

In Star Trek: The Original Series, the transporter pattern buffer records a person's physical pattern during teleportation.

The pattern buffer is part of the transporter system that converts a person into an energy-and-information pattern, temporarily stores that pattern, and then helps reconstruct the person at the destination. It is therefore a crucial intermediate stage between dematerialization and rematerialization.

Star Trek stories often use the buffer to create technical danger. A damaged or overloaded buffer can threaten a transporter's ability to hold or restore a pattern, while unusual episodes portray patterns being stored or recovered for longer than normal. These plots treat the buffer as both a computer memory system and a matter-pattern repository.

The pattern buffer should not be confused with the transporter pad, which is the physical platform where transport begins or ends. The Heisenberg compensator is another transporter component, but it is associated with resolving quantum-mechanical problems rather than storing the pattern.