Call The World For Free
Call the World for Free
(on someone else's nickel)
... with Universal International Freefone Service
This article is not yet another article teaching you how to use VoIP
to make calls (with shitty quality!) to overseas for small fractions
of pennies. Instead, it's an exploration of a neglected corner of the
phone system. Often interesting things collect in dark corners.
I've tried to make this a concise summary of nearly everything I know
about an unusual subject. As such, it will be dense.
You probably know that it's possible to dial international calls at a
horrendously expensive rate right from the telephone in your home, or
for cheaply over a lousy connection using the Internet. Perhaps
you've sighed at the expense, wishing that you were able to call
overseas cheaply and without the hassle of VoIP. (Er, I know *I*
have.) Your wait may be over.
In 1997, the International Telecommunications Union
(<http://www.itu.int/>) created a system called Universal
International Freefone Numbers (UIFNs). In a nutshell, they defined a
/non-geographic/ country code +800, to which calls are toll-free from
everywhere in the entire world. UIFNs are of the format +800 XXXX
XXXX. The actual phone line that your call will go to is at the
discretion of the owner of the number, and can be any phone number in
the entire world. They can contract with their carrier to have it
route to different call centers depending on time of day, traffic
load, and so forth.
 Actually, only from participating nations.
 To dial, replace + with 011 in the US, 00 in Europe, and so
Just like 1-800 numbers in the United States, these calls reverse
bill. The recipient gets to pay through the nose while the caller
(you!) gets a free call. A common rate structure for this service is
a per-minute incoming rate, on top of which there may be a charge per
day or per month for having the number allocated and routable.
The benefit of a UIFN to a number holder is that they offer a uniform
dialling format around the world. This is especially useful in
Europe, where a corporation may do business in multiple countries with
widely varying toll-free number schemes. They can save money with one
set of business cards and advertisements.
-- Behind the Scenes --
I'm going to address this from a United States-centric perspective,
since that's the phone system I know the most about.
When you start by dialling 011, the phone switch flags that as an
international call. It collects all the digits you dial, and then
passes them on to your preferred long-distance carrier for routing and
Your long-distance carrier then must look up the terminating carrier
for the call. The ITU maintains the master list of terminating
carriers for UIFNs, but this list isn't used to route calls. Instead,
each originating carrier is supposed to maintain its own UIFN routing
database. When it's figured out the terminating carrier, it hauls the
call to a location where it peers with that terminating carrier, and
hands it off to them.
This is different from standard international call routing, where the
country and city code is translated to a physical network location,
where the call is then handed to the preferred carrier (usually the
Notably, it's also different from the United States' toll-free routing
scheme, where the number you dial is translated, by a central
database, into another 10-digit phone number and then routed normally.
Each originating carrier maintains its own database, as I said
earlier. Let's say I'm to request a UIFN from British Telecom, and I
want to have it be diallable from Denmark and Sweden. I tell this to
British Telecom, and they get a number from the ITU for me. Then BT,
as the terminating carrier, talks to all the Danish and Swedish
international carriers (Tele2, TeliaSonera, Unisource, and TDC) to
get them to add the UIFN to each of their databases as "routing via
British Telecom". Each carrier must then place a test call to British
Telecom to ensure the number routes properly.
 The listing of UIFN providers, by country, is available at
I'm assuming that these are also the carriers of last resort.
-- Billing --
No discussion of telephony would be complete without a section on how
the billing is done. A phone company without a billing department
just isn't a phone company.
That said, I don't know for certain how inter-carrier settlement
occurs for calls made via UIFNs. I suspect that settlement agreements
are negotiated pairwise between individual carriers, similar to how
the calls themselves are routed. I haven't confirmed this, however.
-- Where can I expect to use UIFNs? --
UIFN dialling is little-known and patchily implemented in the United
States. Some landline switches will accept dialling of UIFN calls,
and some will reject them before you're even done dialling. Whether
the call actually completes is up to your long-distance carrier.
Sprint's, AT&T's, and MCI's long-distance operations all route UIFN
calls properly, provided their routing databases contain the number.
Qwest's doesn't, and I can't say for sure whether anyone else does
My Qwest 0 operator and her supervisor both denied the existence of
country code 800. When I asked why my calls were going through, they
were at a loss for words, and said to call the business office. The
Sprint long distance rate-and-route operator, however, told me without
hesitation that it's a free call that I can dial myself.
And dial I did.
No payphones that I've tried will let me dial UIFNs for free. The FCC
requires payphone operators to allow users to call toll-free numbers
for free. This doesn't apply to UIFNs. Payphones in my corner of
Qwestland (which are operated by FSH Communications) give a CBCAD
recording, the same as when you dial any out-of-LATA numbers.
Out of the five cellular carriers I have access to (T-Mobile, AT&T,
Verizon, Sprint, and Nextel), only Nextel and T-Mobile routed my calls
properly. Notably, AT&T insisted on routing my calls to "+800 ABCD
EFGH" to "+1 800 ABC DEFG". This surprised me, as I expect AT&T to
have the least amount of pretend telephony in their network. Their
long distance service, for example, is usually top-notch. Further
proof that AT&T long distance is completely separate from AT&T
Both of the T-Mobile customer-service people I talked to denied that
country code 800 exists. A call will go through on T-Mobile, if you
have international dialling allowed on your line. (T-Mobile uses AT&T
long distance service, so this is sensible.)
If all this fails you, it's still possible to call UIFNs. From nearly
all landline phones in the United States, you can dial 101-0288-0# to
get AT&T's operator platform. At the prompt, you can then dial
011-800-ABCD-EFGH and your call will go through. You oughtn't get
billed for this call. Other PICs (101-XXXX codes) that I've found to
work are MCI's (101-0555, 101-0222, 101-0888), and Sprint's (101-0252,
101-0333, 101-0872). Some of these work only when you dial
101-XXXX-011-800-ABCD-EFGH, while others only work when you call using
the operator or menu system, via 101-XXXX-0#.
You can't dial PICs from cellphones. Your final refuge here is the
wide range of prepaid phone cards and operator service lines. Since
these tend to be made of Asterisk and pretend telephony, I can't
imagine that very many route +800 calls at all. The only one I have
available is from Verizon. The card platform doesn't route it, and
the card platform's operators refused to dial it for me.
I've mostly given up on trying to get operators to do their job
properly. The nice man at AT&T's free 1-800-OPERATOR service let me
call a UIFN once I told him that it didn't work from my cellular
I've had so many arguments with operators in the past few months about
whether 800 is a country code or an area code in the US, it's
ridiculous. I try to make it clear that I want to dial country code
800. The operator then asks what country that is. I say it's
international toll-free. Then the operator says either "but where
does it go?" or "that phone number is too long, phone numbers are 7
digits". I've had moderate success simply saying that the number goes
On top of all this hassle, most UIFN owners choose to not have them
diallable from the United States. This may be because it's cheaper to
simply get a +1-800 number in the United States and then forward it
overseas, than it is to support customers who sometimes can't dial you
and don't know why not. It's a horrible mess over here.
-- What can I do with UIFNs? --
That's the $25 question.
As someone on the Internet said, "hand-scanning is the pastime of
bored phreakers everywhere". It's a bit of a pain, but there's no
better way to find interesting things on the phone network than
dialling a bunch of sequential numbers and listening carefully.
You can query the UIFN assignment database at
<http://www.itu.int/cgi-bin/htsh/uifn/search/uifn.form> so that you
don't waste your time scanning non-allocated phone numbers. Even
then, most of the numbers that searches bring up won't complete from
inside the United States.
Already, mining search engines for UIFNs, I've found at least a few
conference bridges. Think of that - maybe you can get a whole IRC
channel on a toll-free conference line, courtesy of some corporation
you've never heard of.
It's also just fun to hear the circuits connecting sometimes. Many
UIFNs allocated by Deutsche Telekom are broken in interesting ways
(e.g., +800-2255-3241 or +800-2255-5888). AT&T's worldwide business
customer support hotline at +800-2255-4288 (800-CALL-4-ATT) lets you
press 4 over and over to stack up international circuits. There are a
bunch of other interesting things out there waiting to be found, and
I've only explored the range +800-2255-XXXX in depth.
-- Resources --
The ITU website, <http://www.itu.int/>, is full of information and is
hard to navigate.
If you want even /more/ detail on how UIFNs get activated, the
procedure is described on page 13 of E.152, which lives at
The International Inbound Services Forum operates a database of
carriers offering to receive international calls at