Step by step tones for Telephone Switch Type ATT/Philps Tel 5ESS-PBX Host

This is the step by step tones for Telephone Switch type ATT/Philps Tel 5ESS-PBX Host switches. The first 2 tones are the same. But the off hook tone is different at the end. I still wanna know what kind of off hook tone that was and what the technical name for this off hook tone is. Pease let me know. thank you.