tones

[Gary Kremen]

Hello, I was wondering if any of you people out there in Netland had any
information about the tones that you sometimes get when you dial a wrong
number. For example, if you dial a number that is not in service or one
that is disconnected you get a series of three? tones and a synthetic
voice telling you what you have done wrong.

I was wondering:
1) Are these tones different for different types of messages?

2) Is there a code behind the tone sequence? If there is, what is the
code or where can if find a listing for it?

3) What is the official purpose of the tones? Can the be recognized by a
Touch Tone (tm) decoder?

Thanks in advance.

[j...@ihtnt.uucp]

Many of the tones at the beginning of recorded announcements were originally
put there for a product that the FCC did not let the Bell System
put into service - namely Voice Storage System. It had an answering
capability, similar to answering machines, plus the more interesting
voice mail capability that allowed you to send a voice message at
a particular time. It recognized the tones generated in announcements,
so that it would not deliver a message to an announcement. The tones
are MF (Multi-Frequency, the type of signal that blue boxes used).
MF signals were designed for ease of generation and detection, as
Touchtone was designed for ease of listening.

John Haller