Can the nearest frequencies be searched within the GTR 225?

Does the GTR 225 contain a database?

What versions of the GTR 225 are available?

Can a Garmin portable GPS be used as a position source for the GTR 225 and GNC 255?

Can frequencies be searched by airport identifier?

The GTR 225 will report on the 25 nearest Airports (APT) frequencies, when interfaced with an appropriate GPS receiver and frequency database.

More information about the GTR 225 can be found here