Beep codes for late 2009 iMac

Question

My iMac beeps on startup. Does anyone know the beep codes?

I never actually knew what the beeps were, until I read "How do I reset the time on my computer without turning it on?".

Answer 1

1 tone, a 5-second pause, repeat – No RAM installed

3 successive tones, a 5-second pause, 3 successive tones – RAM does not pass data integrity check

1 long tone when holding down the power button – Firmware upgrade in process.

3 long tones, 3 short tones, 3 long tones – Firmware restoration from CD in process.

http://bamajr.com/2009/06/05/macintosh-post-beeps-defined-part-3/