[Asterisk-Users] How to number extensions - Which way is best?

[Jay Milk]

I'd say, consider your audience (user-base) and let common sense
prevail.

If your user-base is accustomed to business PBXs, they'll already expect
to have to dial a 9 or 7 to "get out".  In that case, number your
extensions any way you like, must avoid that "outside" digit.

Personally, I prefer a "transparent" PBX, and this is my setup:

011... - International calls
1... - NANPA calls
2... - internal extensions
3... - external extensions (SIP/IAX clients)
411 - operator
6... - speed dial
8... - direct trunk access (in my case -- all IAX --, that means it will
set the proper caller-id for outgoing calls)
911 - guess that that's for.

The advantage here is that incoming calls can generally be returned
without any digit-magic, just by selecting a number from the incoming
call-list and pushing Redial or what have you.  Since I use multiple
providers, I have an agi script that "normalizes" this number for me
(http://muware.com/asterisk)

If you have a T1 with a thousand-block of DIDs, I'd recommend
coordinating the extension with the DID#, such that -- 800-555-1234
corresponds to extension 2-1234, and 800-555-4637 can be dialed as
2-4637 internally.  Ditto for voice-mail.

And whatever you decide, make sure that 911 is idiot proof -- allow
calling as 911, 7911, 9911, etc.

> -----Original Message-----
> From: Tim Burt [mailto:asterisk-list at timburt.com] 
> Sent: Monday, February 07, 2005 4:46 PM
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] How to number extensions - Which 
> way is best?
> 
> 
> If this topic has been discussed already, please point me to 
> it.  I have looked, and I don't see any discussion in the 
> past couple of months or in the wiki.
> 
> When setting up your inside extensions, it can be helpful to 
> choose the numbering carefully.  Ideally, you would like it 
> to not conflict with the dialing of an outside number.
> 
> For example, the extension...
> 
> 1212
> 
> Is very similar to dialing a new york long distance number:
> 
> 1-212-555.1212
> 
> The phone company intentionally avoids some number 
> combinations.  Local numbers never start with a "1".  This 
> way, the Phone company switch knows that any number that 
> starts with a "1" needs long distance routing.
> 
> ------------------
> 
> Some switch systems avoid this issue by requiring that 
> extensions dial a 9 to get an outside number.  This allows 
> the use of any extension numbers internally, as long as they 
> do not begin with a "9"!
> 
> I can setup asterisk to work this way.
> 
> ------------------
> 
> What would be a wise choice for your extension numbering if 
> you were just setting up a new system?
> 
> Is there a "better to use" set of extensions, that avoids 
> confusion with dialing of external numbers.
> 
> ------------------
> 
> Or perhaps, I am way off base.  Does asterisk have some magic 
> sauce that makes this a moot issue?
> 
> Thanks in advance. _______________________________________________
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