Almost every country in the world has a dedicated country code assigned to it for telephony purposes (see
countrycode.org for a full list). There is one very large exception to this rule and that is countries in
North America (US and Canada) and a good portion of the Caribbean. These countries all share the same country code of +1 and are collectively part of the
North American Numbering Plan (NANP), which is managed by the
North American Numbering Plan Association (NANPA).
A NANP number consists of the country code +1, a 3-digit area code, and a 7-digit subscriber number, often formatted like +1 (212) 222-3333. You'll sometimes see the +1 omitted from the number on business cards and websites that don't think globally.
Dialing numbers in North America is quite different from most places in the world. In the rest of the world, if you want to dial a long-distance or national number, you have to dial a national access code. In a lot of countries, this number is 0. However, in NANP countries, you have to dial 1 for long-distance/national numbers. That's right, you have to dial the
actual NANP country code as the long-distance access code, which is unique among all other countries. Incidentally, the international access code is 011 (in many other countries, its 00).
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If you want to dial Canada from the US, or the US from Canada, or any of the Caribbean countries in NANP, you don't dial the international access code 011, you just dial the number as you would any other long-distance number. So, if I want to dial Toronto, Canada from Vancouver, Canada I would dial +1
416 555 1111. If I wanted to dial New York City from Vancouver, I'd dial +1
212 555 1111.
It gets even better. NANP area codes are allocated by a trio of over-caffeinated spider monkeys who press numbers on a giant keypad at random to assign a new area code (well, that's how it appears). There is no logical separation between area codes between any of the countries. For example, area code 646 is in New York, USA, 647 is in Ontario, Canada, and 649 is in the Turks & Caicos (Caribbean island nation).
Click here for a current list of area code allocations in NANP.
These days, calls between the US and Canada are often priced identically to a domestic long-distance call. But calls to the NANP Caribbean countries are usually priced much higher, akin to dialing some very remote international destinations. Continuing the previous example, a US user that has signed up for Microsoft's
Skype for Business Online PSTN Calling Plan can expect to pay $0.013 per minute (just over 1 cent a minute) to call area code 647 in Ontario, but would end up paying $0.583 (almost 45x more expensive) to $0.741 per minute to call area code 649 in the Turks & Caicos.
Since it is nigh impossible for a regular person to distinguish a Caribbean country from US/Canada based solely on the area code, it is easy for people to accidentally incur high phone charges when calling these countries.
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Skype for Business administrators often want to prevent certain users from dialing these Caribbean countries, and it can be easily done with some fancy routing rules. Assuming you've already configured voice polices for national and international access, then you just have to modify the National level voice route to block Caribbean destinations. You could do some research to determine the Caribbean area codes, and create your own regular expression to block them, but I figure I should do SOMETHING useful with this post and provide you with that information.
This Skype for Business route number pattern will block all Caribbean countries that are part of NANP, except for the US Virgin Islands and Puerto Rico (which are often not priced much differently than US numbers, when calling from the US):
\+1(?!(24[26]|26[48]|284|345|441|473|649|664|721|758|767|784|8[024]9|86[89]|876|900|976))[2-9]\d\d[2-9]\d{6}$
If you want to also block US Virgin Islands and Puerto Rico, then use this one:
^\+1(?!(24[26]|26[48]|284|34[05]|441|473|649|664|721|758|767|78[47]|8[024]9|86[89]|876|900|939|976))[2-9]\d\d[2-9]\d{6}$
You may note that I've also made sure to exclude premium area codes like 900 and 976.
To make sure that people assigned an International voice policy can dial those Caribbean countries, your international route should include a pattern for North American numbers and look something like this:
^\+((1(?!(900|976))[2-9]\d\d[2-9]\d{6})|([2-9]\d{6,14}))$
If you REALLY wanted to get draconian and block calls to Canada from the US, and vice versa, you could use the following rules:
Block Canadian and Caribbean calls:
^\+1(?!(900|976))(20[^04]|21[^1]|22[4589]|23[149]|24[08]|25[12346]|26[0279]|27[026]|30[^06]|31[^1]|32[0135]|33[^2358]|34[067]|35[12]|36[01]|38[056]|40[^03]|41[^168]|42[345]|43[0245]|44[023]|47[0589]|48[04]|50[^06]|51[^149]|53[0149]|54[01]|55[19]|56[12347]|57[01345]|58[056]|60[^04]|61[^13]|62[03689]|63[016]|64[16]|65[017]|66[01279]|67[018]|68[124]|70[^059]|71[^01]|72[0457]|73[1247]|74[037]|75[47]|76[02359]|77[^1678]|78[1567]|80[^079]|81[^19]|83[012]|84[3578]|85[^1235]|86[02345]|87[028]|90[^025]|91[^1]|92[0589]|93[16789]|94[0179]|95[12469]|97[^4567]|98[0459]|281|458|469|520|828)[2-9]\d{6}$
Block American and Caribbean calls:
^\+1(?!(900|976))(41[68]|43[178]|51[49]|58[17]|70[59]|78[02]|90[25]|204|226|236|249|250|289|306|343|365|403|450|506|548|579|604|613|639|647|778|807|819|825|867|873)[2-9]\d{6}$
The above rules are formatted slightly differently from the ones that block Caribbean countries. The Caribbean rules show which area codes to BLOCK. The other rules show which area codes to ALLOW. Of course, I didn't roll these rules by hand, since there are tens of dozens of area codes allocated to each country, and do change from time to time. I used the super handy-dandy
Lync Optimizer. As you might expect, these options are available in the
Lync Optimizer via the "
Treat as National" option (only shows for North American dial rules). You can select one of the following options with regards to dialing other countries within NANP:
- In-Country Only - Treat all calls to NANP countries other than your own as international, even though users don't have to dial 011 to reach them. As such, users will have to be a member of a voice policy that allows international dialing.
- US/Canada - Treat calls to anywhere in US/Canada as national calls, excluding the Caribbean. To dial Caribbean countries, users will have to be a member of a voice policy that allows international dialing. Not available for Caribbean rulesets.
- US/Canada/Caribbean - Treats calls to anywhere in NANPA (US/Canada/Caribbean) as national calls (along with the potentially higher call costs).
If you are creating a ruleset for a Caribbean country that uses +1 as the country code, you won't be able to select
US/Canada, since this would make dialing within that Caribbean country difficult.
Selecting the
Simple Ruleset option prevents usage of this feature, and will default to
US/Canada/Caribbean. You won't be able to control how people dial other NANP countries when there is only a single simple routing rule.
So, there you go. A lesson in the finer details of dialing numbers in North America that the rest of the world might not be aware of. Try to contain your excitement.
