I've seen the pedestrian signals for visually impaired in some places as well; they are common around San Gabriel particulary along Valley Blvd and near Cal Poly Pomona as well.
The ones along Valley are these small speakers mounted on top of the pedestrian signal with a speaker on the front. A Chirping noise is used for East and West and Cuckoo for North and South.
The ones by Cal-Poly are actually built into the pedestrian head itself. I'll try to get a picture the next time I'm in that area. The same tones are used.
I've visited my relatives in Hong Kong once and they had a similar system only their signals emit "clicking" noises. A slow click is for Wait (Don't Walk) and a very fast clicking is for Walk.
http://www.youtube.com/watch?v=girJVjBVt28