Keyless entry and key programming on the Miata depend heavily on year, because early cars have no immobilizer at all while later cars tie the key to the engine computer. Know which car you have before buying keys or fobs.
Early NA and NB cars use a plain mechanical key with no transponder, so any cut key starts the car and there is nothing to program. Keyless entry, where fitted, is a separate remote for the door locks only
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