TELECOM Digest OnLine - Sorted: Re: Telephone Area Codes and Prefixes

Re: Telephone Area Codes and Prefixes

Neal McLain (nmclain@annsgarden.com)
Tue, 27 Feb 2007 22:26:24 -0600

I wrote:

> So how would they pronounce 201-200-0000?

Bob Goudreau wrote:

> The other cool thing about that number is that it is of
> course the lowest (generally-dialable) phone number in
> the entire world!

Ron Kritzman wrote:

> In the telephony world 0 is a ten not a null, so
> wouldn't that be a pretty high number?

PAT wrote:

> I think that all depends; if you are dial pulsing the number it is a
> 'ten'.

Robert Bonomi wrote:

> True for North American phone systems.

> There are other, incompatible, phone systems that use different
> encodings. One uses two through eleven pulses for the digits, with
> 'n+1' pulses for 1-9, and eleven pulses for '0'. This greatly
> reduced false-digit detection from the equivalent of a 'switch-hook
> flash'.

You may be thinking of Sweden. http://tinyurl.com/2h7jde

But note that on the Swedish dial, zero is encoded as one pulse, not
eleven. Of course, that would still prevent wrong numbers due to
false-digit detection: the caller would get the operator.

Assuming, of course, that "false-digit detection" is actually a
problem. I always thought it was, but our friend Wes Leatherock
thinks otherwise. Wes?

PAT continued:

> Exactly how it [digit zero] is translated if being 'tone dialed' is
> not known to me. Is it still considered a 'ten'. In that case, are
> the '*' and '#' keys considered eleven and twelve when dialed? PAT]

Tone dialing is accomplished by transmission of two audio tones within
the 300-3000 Hz voice bandwidth; hence the terminology "dual-tone
multi-frequency" (DTMF) signaling. Each digit (including *, #, A, B,
C, and D) is encoded by a different combination of a set of eight
audio tones. Digit zero is encoded as 941 Hz + 1336 Hz.
http://tinyurl.com/22gu3j

No matter how we encode numeric digits, we have to assign *something*
to represent zero. We can't represent zero by nothing at all
(although I've been told that Roman numerals don't have a zero). Over
the centuries, we humans have evolved numerous conventions: 0, 000,
0000, 0x00, "zero", "oh", "null", "nought", "goose egg", "zilch",...

In the telephony world, zero can be encoded as one pulse, ten pulses,
eleven pulses, 941+1336 Hz, or whatever. But for the purposes of
assigning human-readable telephone numbers, a zero is a zero is a
zero.

Therefore, I agree with Goudreau: 201-200-0000 is the lowest
(numerically) in the NANP.

And I suppose that:

- If you're counting dial pulses, the lowest would be 212-221-1111
(except that it might be tied with 212-212-1111 if the Illinois
Commerce Commission were assigning NNXs in New York).

- The highest (numerically) would be 989-999-9999, in an unassigned
NPA-NNX in Michigan.

- The highest (counting dial pulses) would be 909-900-0000, an
unassigned number in the Fantana, California rate center.

Neal McLain

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