11-Digit Dialing - Why Mandatory?
Ron Walter
> [TELECOM Digest Editor's Note: Many people believe the '1' on the
> front does more than just alert the switch regards the context of
> the next three digits dialed; it also serves to remind the user
> that a toll call is happening, a call that may cost them extra
> money. PAT]
There is an equipment consideration. Many home telephones, key
systems, and PBX's have toll restriction features that look for the
first few digits dialed to determine whether to allow calls to go
through. Most systems, especially the older ones, look for a 1 at the
beginning to make that determination. If you want to allow local
calling at particular phones but not allow long distance calls, you
need that toll restriction feature.
If you remove the 1+, many businesses are forced to replace their
systems or add on equipment that can keep a table of which numbers are
long distance and which are local. It also requires you to spend a
great deal of time keeping up with what are local and what are not.
This usually means spending more money on having the system vendor
take care of those things.
An example in Southeast Nebraska came when the Local Exchange Carrier,
Aliant Communications, introduced a new enhanced calling area plan.
Part of that plan allowed people to call to communities within a 25
mile radius by simply dialing a 7 digit number. Those numbers would
have toll charges related to them. It created quite a problem with
places like schools and manufacturing plants who had students or
employees who lived in those areas and who could now call those
numbers because their systems' toll restriction feature was rendered
ineffective without the 1 in front of the numbers. It led to either
replacing their phone system, paying for their equipment vendor to
come out and build toll restriction tables, or just stop allowing
calls altogether. Companies in the interconnect business got some
good benefit out of it (by the way, guess who the largest vendor of
phone systems and PBX's in the area is? Aliant Communications).
[TELECOM Digest Editor's Note: Years ago we used to look for zero or
one as the first digit and zero or one as the second digit (since
only area codes had zero or one in the second spot) and deny the call
on that basis. You can still deny on zero as the first digit and have
billed number screening in place (no manual charges to be placed on
this number by an operator) but screening for one as the first digit
won't even work in a place like Chicago where crossing of area code
boundaries is still considered a local call in many cases. And of
course with overlays there will be a lot of 1+ calls just around
your own neighborhood. I do not know any effective way to screen
the digits dialed these days except for using a table which says to
deny all except (these three) or something like that.
Radio Shack sells a toll deny device which can go in some secret
place at the head end of your pair, right before it reaches the
demarc so that everyone has to pass through it. The admin can
program it remotely using a password, and other passwords can be
used by callers as 'authorization codes'. The admin can tell it to
(for example) allow 312,630,708,773,800,847,888,877 as the only
acceptable combinations with a '1' in front (all are local or no-
charge combinations in the Chicago area) and to disallow all other
combinations which began with '1', also to deny 900 by virtue of
it being disallowed because of '1' on the front, deny 976, 555 or
411 (premium charge for directory assistance), etc.
Trouble is, you have to keep the little box itself well-hidden, since
anyone who unplugs it for a minute or does a 'hard reset' will cause
it to forget everything it knew before. On the other hand, if someone
steals root from the admin by getting his password, all he has to do
is go unplug the device and start over with the factory defaults
again. If the admin only wants a certain phone to be restricted, then
the little box is placed in series on that local portion of the pair;
others ahead of him are unrestricted. If it is placed in series at the
head -- which would seem to be the only worthwhile way of doing it --
then everyone downstream is toll-restricted.
A user dialing a forbidden number hears a second or two of silence,
followed by a 'click' and fresh dial tone. You need one device for
each outgoing trunk especially if you cannot be sure which outgoing
trunk will be seized by the user at any given time, such as dialing
'9' on a PBX and getting an available line. I think root gets a
six digit passcode while other users get a four digit bypass code if
authorized to make calls. I hope Radio Shack has not taken that
out of stock; so many of their more esoteric and seldom-sold phone
products are no longer available. PAT]
Leonard Erickson
> My area code 408 (San Jose, Calif) is getting an overlay soon, and
> we'll all be dialing many digits.
> I understand why I'll need to dial the new (overlay) code when
> calling a number in that area, but why the need to dial my own area
> code when *not* calling out of it? Is this not exactly analogous to
> calling (say) to another state?
> Seems to me that the same trigger (the 1-) would distinguish between
> my own (no 1-) and the other (1-xxx) area. So why is it mandatory?
Well, for one thing, you can dial an overlay number *without* a leading
1-.
The big thing is this: How are you going to know which of the two area
codes the phone you are *using* is in? If it's your own personal phone,
maybe. But for any other phone you'd have to *look*.
And a given switch may be handling exchanges in *both* area codes.
Which makes the programming a real problem, because it'd have to use
different dial decoding rules based *solely* on the line ID, which is
based on the wire pair, *not* the assigned telephone number.
For that matter, If I get a distinctive ring number added to my
existing number, they could be in *different* area codes. So which one
is "the" area code for the number?
There are also other issues involving reserved exchanges and adjacent
area codes, but that gets a bit technical. Suffice it to say that once
an overlay goes in, you are stuck with 10-digit dialing for local
calls.
Also, in not that many years, even *non*-overlay areas may have to
switch to 10-digit local dialing.
Leonard Erickson (aka Shadow)
sha...@krypton.rain.com <--preferred
leo...@qiclab.scn.rain.com <--last resort
Linc Madison
(Leonard Erickson) wrote:
> Jim Van Nuland <j...@svpal.org> writes:
>> My area code 408 (San Jose, Calif) is getting an overlay soon, and
>> we'll all be dialing many digits.
>> I understand why I'll need to dial the new (overlay) code when
>> calling a number in that area, but why the need to dial my own area
>> code when *not* calling out of it? Is this not exactly analogous to
>> calling (say) to another state?
>> Seems to me that the same trigger (the 1-) would distinguish between
>> my own (no 1-) and the other (1-xxx) area. So why is it mandatory?
> Well, for one thing, you can dial an overlay number *without* a leading
> 1-.
Incorrect. You CANNOT dial an overlay number IN SAN JOSE, CALIFORNIA,
without the leading 1 (effective October 1999).
In California, 10-digit dialing without the leading 1 is always and
absolutely forbidden. If you dial 1, you must dial an area code, and
conversely if you dial the area code, you must always dial 1 or 0
first. California does not use the "1+ means toll" rule at all.
> The big thing is this: How are you going to know which of the two area
> codes the phone you are *using* is in? If it's your own personal phone,
> maybe. But for any other phone you'd have to *look*.
> And a given switch may be handling exchanges in *both* area codes.
> Which makes the programming a real problem, because it'd have to use
> different dial decoding rules based *solely* on the line ID, which is
> based on the wire pair, *not* the assigned telephone number.
> For that matter, If I get a distinctive ring number added to my
> existing number, they could be in *different* area codes. So which one
> is "the" area code for the number?
All true.
> There are also other issues involving reserved exchanges and adjacent
> area codes, but that gets a bit technical. Suffice it to say that once
> an overlay goes in, you are stuck with 10-digit dialing for local
> calls.
This is why California does not permit 10D dialing of any calls. For
example, the 408-925 prefix is local to some exchanges in the 925 area
code. Before the introduction of mandatory 1+10D in 408, you would
have a conflict between 925-xxxx and 925-nxx-xxxx.
> Also, in not that many years, even *non*-overlay areas may have to
> switch to 10-digit local dialing.
True, although right now the CPUC is reconsidering its overlays because
of consumer resistance to mandatory 1+10D.
** Do not send me unsolicited commercial e-mail spam of any kind **
Linc Madison * San Francisco, California * Telecom@LincMad-com
URL:< http://www.lincmad.com > * North American Area Codes & Splits
>> NOTE: as an anti-spam measure, replies are set to "postmaster";
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Neal McLain
Erickson) writes:
> Also, in not that many years, even *non*-overlay areas may
> have to switch to 10-digit local dialing.
If/when the entire NANP goes to 10- (or 11-) digit dialing on all
calls, we should be able to use 1 and 0 for the first digit of the NXX
code -- turning it into an XXX code. Thus, combinations such as
415-120-9905 and 415-020-9905 would be valid. This would result in a
25% increase in the size of the number pool.
Is this likely to happen?
Neal McLain
nmc...@compuserve.com
[TELECOM Digest Editor's Note: At the present time, many of those
three-digit combinations as per your examples are used. They are
non-dialable, of course, for billing purposes only. Things like
'non-subscriber calling cards' from AT&T (calling cards issued
where there is no specific telephone number to relate it to), tie-
line circuits between PBXs, the older style 800 number which had
its termination on a circuit of its own not related to any specific
seven-digit number as most are today, etc. Many of them are also
dialable by telephone operators only as a way to reach the 'Inward'
operator in some other city.
A miscellaneous billing account in Chicago for example might be
something like 312-173-2901. Like an actual, dialable prefix, some of
those non-dialable 'billing pur- poses only' three digit combinations
are assigned to local telco, some to AT&T, some to MCI, some to
Sprint, etc so that clearinghouse functions can be handled with ease,
with the area code and first three digits detirmining which telco is
to get the associated charge or credit. If a toll ticket for example
was to be billed to the number (example) 305-099-7234 then telco's
back office could look at it and detirmine that the charge should go
to Sprint to some miscellaneous account at their office in Miami.
Just as for many, many years when we had 'traditional' area codes,
the number '909' was never assigned to telephone use because it was
in use by Telenet as the 'area code' for their data network, when
it was eventually taken over, Telenet had to do some re-arrangements
on their own network. The numbers you suggest are already 'known'
by telco computers, its just that they are known to serve other things
than actually connecting to a live customer. To assign them now as
phone numbers would require all sorts of changes in things like the
operator's routing tables for inward, billing functions, and whatever
else. I suspect a lot of backoffice bureaucrats would be hostile.
Besides, there are other ways to expand the supply of numbers, and
telco would rather inconvenience the public with area code overlays
and eleven digit dialing anytime in preference to having to be
inconvenienced itself in its own internal functions. PAT]
Dave Close
> If/when the entire NANP goes to 10- (or 11-) digit dialing on all
> calls, we should be able to use 1 and 0 for the first digit of the NXX
> code -- turning it into an XXX code. Thus, combinations such as
> 415-120-9905 and 415-020-9905 would be valid. This would result in a
> 25% increase in the size of the number pool.
I've seen the good reasons why this is unlikely. But I note that, if a
leading 1 is required on all calls, that we have effectively made area
codes four digits, all of which start with 1. It wouldn't be a big
stretch to then start to use the other possible four-digit codes.
Of course, current 0+ calls would have to change to 12 digits. And
there would be other adjustments for 01 and 011 calls. But those
changes would probably be minor compared to the increase in numbers.
Dave Close, Compata, Costa Mesa CA "Politics is the business of getting
da...@compata.com, +1 714 434 7359 power and privilege without
dhc...@alumni.caltech.edu possessing merit." - P. J. O'Rourke