1992 Toyota Celica. I've been trying to program a keyless entry, with failed results. With an old model like this, is it possible? If so, how?

TRY, this. . To program a REMOTE CONTROL to the system: 1. Insert the key into ignition switch, and turn it to “ON”. 2. Press and hold the ECU’s PROGRAMMING SWITCH for 3 seconds. The STATUS MONITOR LED turns on for 5 seconds. NOTE: YOU MUST PERFORM THE NEXT STEP WITHIN 5 SECONDS. 3. Press and release a REMOTE CONTROL’s top or bottom button. The STATUS MONITOR LED turns off. The Piezo “chirper” chirps once. The exterior lights flash once. 4. Turn off the ignition. The ECU will now operate with the REMOTE CONTROL just programmed. Either button on your REMOTE CONTROL can be programmed to operate the system. The bottom button can be programmed to operate a second vehicle with the Toyota VIP. Programming Procedure Press and Hold for 3 Seconds Lights Up Press Once