GTD-5 EAX Forum - Receiver Off Hook Tone For G.T.D.-5 E.A.X.

GTD-5 EAX Forum - Receiver Off Hook Tone For G.T.D.-5 E.A.X.   Is the R.O.H. tone for the GTD-5 EAX a siren of a buzzer? The off hook tone for a GTD-5 EAX. may be a reffered to as a high tone. But it said the high tone is 480 Hz. But when I was a kid back living in Farragut in 1979 to1981 I don't recall it being that high pitch. I though it was a medium pitch sound. Now could there be other systems? like ESS switches? Are ESS switches conected to GTD-5 EAX switches or are they different? Now is the warbling siren sound that reffered to as a howler tone build into the GTD-5 EAX system or is the so called howler tone with a different phone system?