[Asterisk-Users] Not answering inbound a line used for outbound

[Rich Adamson]

> I've dug a bit through the wiki and the mailing lists, and haven't really
> seen anything like this, but there must be someone out there doing this.
> 
> Basically, there is a fax line that I don't want to answer inbound, but I
> want it available to do dial out from. Right now, we are using a busy wait
> around the ringing line, but I was hoping for something that might be a
> little more elegant. Here is the dialplan snip:
> 
> exten => s,1,Wait(1)
> exten => s,2,GoTo(s,1)
> 
> If I'm on the console when a call comes in, it loops through this bit of
> code a bunch of times. I'm guessing I could lengthen the "Wait(1)" time,
> but is there any other way to do this?

Sure there is, but without knowing what type of pstn interface your
using, can't suggest an exact coding method. For me (with a TDM-fxo card),
the zapata.conf entry for that channel has a context=nowhere kind of
statement. Since the "nowhere" context doesn't exist, nothing in asterisk
will answer that pstn line.

You can also use one of the fax detect mechanisms (including spandsp) to
sense incoming calls, and if its an incoming fax call send it to a 
message that says "this number doesn't accept fax calls" (or something
like that). The folks that generate junk faxes won't listen to it (since
they are automated anyway), but real fax users might. We use that
mechanism when a fax number changes; let your live customers know the
number has changed kind of thing.

> Now, two other related questions:
> Can Asterisk recognize that something other then a Zap card has a line
> offhook? (ie there is a fax transmission in progress)

You'll have to clearify the above better. If you're asking about another
bridged phone on the same analog pstn line, no asterisk doesn't currently
have code in it that would recognize speech on the line, lack of a dial
tone, or any other parameter that would suggest the line is in use. (The
TDM card's chipset can detect it, but the code isn't in asterisk to take
advantage of it.)

> Can I do something interesting with CallerID? (for example, create a log
> of all faxes that called us, or answer certain numbers inside of asterisk)

Sure you can. Take a look at the various README files in:
 /usr/src/asterisk/doc
and particularily the README.variables file.

However, be careful with CallerID assumptions. Telemarketing and junk fax
generators typically disable sending any CallerID info, so it won't be
all that useful.
 
> Do excuse me if this is all answered in some concise FAQ, but I've been
> seriously looking and haven't seen anything about it.

There are lots of good references that come with the asterisk source code
including the doc directory noted above, samples of various configurations
in the configs directory, and the wiki (amoung others).