On Thu, 2005-10-13 at 21:46 -0400, Michael Richardson wrote:
>   a) make sure you have at least one PSTN line, and have a distinctly 
>      coloured POTS phone plugged into it with the ringer off. 
>      That's your 911 line, and it will work when the power is off.
>      You can program Astarisk to ring that line when an extension dials
>      911. Whether you use the line for anything else, is up to you.
>      Maybe it has your DSL on it, or your fax machine.

I'm won't say I disagree with this concept, whatever makes the client
feel safe is the right thing for them. However, let me offer this
alternative.

I don't recommend the above for the following reasons.

First of all, it makes the client feel like the system is inherently
unsafe and inferior to other solutions and this is not true.

What I'm curious about is why suddenly this became an issue only since
VoIP since many (most?) PBXs do not work when the power is out (mainly
because digital handsets require power) and this has been a common
implementation since at least the 80s.

It also doesn't make much practical sense in anything except a very
small office. Running to the red POTS phone on the far side of the
warehouse or 3 floors up the stairs in the office tower (since elevators
don't work in power failures) isn't a good idea. Just get out! If you
really need to call 911 its much safer to do it on your cell phone from
across the street.

If phone service in a power failure is truly a concern for the client
then put Asterisk and a switch with POE (power over ethernet) on a UPS.
Then buy phones that support POE and you have a completely self-powered
phone system. Thats more than you get with most PBXs, especially older,
cheaper ones.

As an added bonus you don't need to use power cubes at every
work-station.

-- 
John Lange


> 
>   b) you may find that buying different services from different
>      providers makes sense.  Don't get locked into a provider that
>      does not do SIP, since not all numbers are portable.
> 
> - -- 
> ]       ON HUMILITY: to err is human. To moo, bovine.           |  firewalls  
> [
> ]   Michael Richardson,    Xelerance Corporation, Ottawa, ON    |net 
> architect[
> ] [EMAIL PROTECTED]      http://www.sandelman.ottawa.on.ca/mcr/ |device 
> driver[
> ] panic("Just another Debian GNU/Linux using, kernel hacking, security guy"); 
> [
> 
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