[Asterisk-Users] Still trying program -> phone call

John Chambers jc at trillian.mit.edu
Thu Apr 1 15:35:09 MST 2004


A while back, I asked about using Asterisk in a medical environment where the task
is to write a program that connects to a phone and sends a message like:

     Hello Mrs. Jones. How are you doing today? Press 1 if you're
     OK.   Press  2 if you need help.  Or start talking, and your
     message will be passed to a person.

After connecting and sending the sound file, the program would obviously need to
listen for keys and voice, and do something sensible with them.

Since then, I've done a bunch of installing, testing, and especially experimenting
with variants of the sample.call file.  So far I haven't been able to answer the
question of whether what's wanted is possible.  Maybe a couple of questions that
we've come up with will clarify things.

One is whether we can make a call to a regular land-line or cell phone, or just
to VoIP-type phones.  If it's possible, what do we need to know about routing?
We're guessing that we need to somehow relay through some sort of IP-to-PSTN
gateway, but information on this seems to be rather muddy.

Asking our local telcos (and Boston has a bunch of them ;-) gets a lot of clueless
responses. If we mutter the acronym VOIP, they perk up and start trying to sell us
their promised VOIP phone service.  But this has nothing to do with what we want
to do, which is to get a *program* to make the call.  This obviously implies that
the connection escapes from the IP cloud and enters the PSTN cloud, but how? If
we need to purchase service with some gateway provider, how do we ask for it?

Actually, I've been really tempted to get a WiSIP phone, to get familiar with
that.  But as far as I can tell, it would just take time away from the real
project, so I haven't. OTOH, if using it would make VoIP clearer to us newbies,
maybe it would be a good idea. Or maybe a softphone on my Powerbook would be
a better way to go.  Or both?  In any case, talking to a SIP phone isn't very
interesting to us yet, since few people have them.  A demo would have to be
to the phones on people's desks or in their pockets.

Meanwhile, another sort of question is how to find explanations of asterisk's
many cryptic error messages.  For example, after cleaning stuff out, downloading
from CVS, doing a make and make install (and ignoring errors ;-), then firing
up "asterisk -vvvc" and copying one of my test*.call files to the outgoing
directory, I got:

*CLI>
     -- Attempting call on Zap/1/12223334444 for 800 at callme:2 (Retry 1)
Apr  1 16:29:08 NOTICE[17424]: channel.c:1563 __ast_request_and_dial: Unable to request channel Zap/1/12223334444
Apr  1 16:29:08 NOTICE[17424]: pbx_spool.c:199 attempt_thread: Call failed to go through, reason 0

(I replaced my home/cell number with 2223334444 for illustration's sake.) Anyway,
I haven't yet succeeded in digging explanations out of www.voip-info.org.  And
that 800 at callme:2 is a bit of a mystery; I see it all the time but have no idea
why it's there.

Further clues (or hyperlinks to clues) are welcome.

I would like to report that "Yes, Asterisk can do that."  So far my report has
to be "Well, maybe, but I can't really tell yet."

(We're also well aware of the serious potential for phone spam in this project.
My reaction tends to be "Not if I can block it."  But it's something that's
obviously going to be a problem in a few years. ;-)





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