Discussion List for Freenum/ITAD Subscriber Number (ISN) Project

[(John R Covert)]

>The suggested prefix for ISN dialing for North American locations
>is "012" (to compliment the "011" that is familiar for international
>dialing.)

I've been meaning to grumble about this for years.  012 has
always been a difficult choice in general, even in North America.

In North America, "01" is the prefix for Operator-Assisted (e.g.
calling card, collect, person-to-person) international calls.

Using "012" for ISN in a dialplan in which "9" is not required
for outside access conflicts with dialing any country in World
Numbering Zone 2.  However, it is common in private phone systems
for various special service access codes to begin with "8", and I
have personally adopted "8012" as the ISN access code in my own
dialplans.  I don't necessarily propose that for others.

I'm not convinced that there is any good ISN prefix; I'm
familiar with one organization which went with *00 as an
access code, not prefix (i.e. you had to wait for a prompt
after dialing *00 because the switch really had no way to
allow an embedded "*" in a variable length number, so the
call had to be passed to an adjunct server).  However,
this particular organization has never (as far as I know)
provided any access code at all in its newer VoIP switch,
leaving the only method of making an ISN call being to dial
a little-known 5-digit extension and wait for the prompt.

>So the recommended ("SHOULD") method would be to not start local
>number portions with zeros, but it is not prohibited.

If an ITAD is an organizational number, then at least "0*ITAD"
should be expected, and at least following the Continental
model for countries with variable length numbers, "0*ITAD"
is the recommended "main number".

In the Continental Model for variable length numbers, you
"know" -- that is, it is officially recommended by the former
PTTs -- that if a number is written as 1234-123, a PBX is
involved.  The "-" has official meaning, explained in the
introductory pages of the telephone book.   These intro
pages explain that you can drop the portion after the "-" and
replace it with a "0" (formerly "1", but changed to "0" some
years ago) to reach the Main number.  This interestingly
makes this particular way of dialing the "main number"
undialable from inside where "0" is usually used in these
same countries as the access to the outside.

/john