Look at the center top of the tachometer---if there's a rectangular LED with the word "Security" next to it, you have a transponder key. And you may have a factory alarm too.
Be sure the hood and trunk are closed. Open the door, press "power lock," and close the door....what does the Security light do? If it just keeps on flashing slowly, you have a transponder key only. If the light comes on steady for thirty seconds and then starts flashing, there's a factory alarm too...and it's necessary to send a low-current ground to the key sense wire during remote start.
I use the Audiovox AS-TCBM, which is just like the 555U, and it works great. The 555F will keep the customer from losing a spare key, but I haven't used one on a Toyota before.