Alpine once made three different alarm system remote controls with the FCC ID B23AT51. Beware: these three parts are not interchangeable, even though they have the same FCC ID and look identical. Alpine’s part numbers usually appeared on the back of the case for these parts, along with the FCC ID. One remote has part number 8426 or SEC-8426. A second keyfob has part number 8426A or SEC-8426A. The third remote has part number 8449 or SEC-8449.
Alpine left the aftermarket alarm system business long ago, so none of these parts are still made. However, Remotes Unlimited (RUI) has a limited stock left of part 8449 (SEC-8449). If you are seeking a replacement for part number 8426 or 8426A, RUI can only help if your original remote can still transmit any signal (even a weak one). If so, RUI can make a copy of your old remote.