[Asterisk-Users] Basic Answering Machine Function?

[Jay Milk]

Good questions...

> -----Original Message-----
> From: Craig Stephen [mailto:craig.a.stephen at gmail.com] 
> Sent: Monday, January 31, 2005 3:59 PM
> To: asterisk-users at lists.digium.com
> Subject: [Asterisk-Users] Basic Answering Machine Function?
> 
> 
>     You might rather have asterisk share the PSTN-provided dialtone 
>     with the other phones in your house, and just pick up 
> when nobody answers,
>     take a voicemail (or play them back to you when you call in from
>     somewhere else), and hang up.
> 
>     Is this possible with asterisk?  Anyone have a sample dialplan?

It's possible -- you'd have something like
[incoming]
exten => s,1,Wait(20)
exten => s,2,Answer
exten => s,3,Voicemail

And that would be your only context.  If you want to get IVR'ish when
checking your incoming messages, you can write another context for that.
The problem is that there's really no telling *what* asterisk will do if
you pick up the phone *while* it's recording a message -- unlike an
answering machine, it likely won't hang up by itself.  I would consider
running the PSTN line *through* asterisk, using an FXO and an FXS
interface (Sipura 3000 comes to mind).  It's some extra money, but it
provides you additional functionality such as telemarketer handling, DND
modes, or even call-recording.

>     That leaves another problem - retrieving the messages.  Sounds
>     like console GUI or web interface would be the only way 
> to do this -
>     since the only way to get connected to the voicemail service
>     is by calling in through the PSTN - since asterisk doesn't "own"
>     any extensions.  Do I have this right?

Correct -- an easy out to this option is of course EMAIL :)  Asterisk's
voicemail can be configured to send an email for each message received,
including a sound-file attachment.  Or, the option of running your PSTN
line through * would allow you to check voicemail from any extension
phone.
 
> 2.  Now, a more full-blown home-use scenario.
> 
>     Is it in principle possible to create a dialplan that allows
>     prefix-free dialing to an outside line, and move all the
>     "PBX-like" features behind some special prefix?
> 
>     i.e. recognize 3, 7 and 11 digit numbers as phone numbers
>     and dial them without further ado, and put voicemail and
>     every other PBX-ish feature behind, say "#"?

As for 7 and 11 digit numbers, I have something like that in place -- my
"wife-friendly" PBX only has the requirement of dialing all numbers as
11 digit numbers.  The dial-plan is fairly simple as such -- "1"+10
digits is always an outgoing call; "2"+2 digits is an extension; "6"+2
digits is speed-dial, etc.  *123 is voicemail here.  You could implement
the 7-digit dialing using your own handy-dandy list of local prefixes,
but I recommend against that.  Using mandatory 11-digit dialing makes
returning calls (from caller-id) easier, and you don't have to change
your speed-dials when you move, or your area code changes -- and the
latter seems to happen more often than the former.
 
Three digit numbers are easy as well -- 911 goes through directly, 411,
is ignored because it's ridiculously expensive, and 311 isn't really all
that interesting.

I'm pretty sure I posted parts of my dialplan last year, but don't have
access to it right this minute.