External keyboard

From TreoCentral

External Keyboards can be useful for entering large amounts of text into a Treo, for example taking notes during a meeting. Most external keyboards currently available for Treos are either infrared or bluetooth, meanting they are wireless. The advantage to a wireless keyboard is that it should typically work with future devices (especially, as of this writing, a bluetooth keyboard. The downside to a wireless keyboard is that it sometimes takes a bit of setup initially to work.

There are non-bluetooth keyboards available for Treo 600s at least.

Most external keyboards that work with the Treo are foldable.