How do I find out which code is already programmed for a device using Code Identification?

Press SETUP until the LED is permanently lit, select the device using the device key, then press SETUP again — the LED will flash once followed by permanent light. Press the numeric keys 0–9 to identify each digit one at a time; the LED flashes once when the correct digit for that position is found. Repeat this process for all four digits of the code. (Pages 6–7)