asterisk users - Feb 2011 - [1.4/AGI] CHANNEL STATUS never "down & available"?

Hello

I'm using an AGI script in Lua to make a callback through Zaptel.

For this to work, I must wait until the channel is idle, or I get this
kind of error, even after waiting over 10 seconds after the remote end
rings once and hangs up:
=============channel.c:2863 __ast_request_and_dial: Unable to request channel
Zap/1/123456
pbx_spool.c:341 attempt_thread: Call failed to go through, reason (0)
Call Failure (not BUSY, and not NO_ANSWER, maybe Circuit busy or
down?)
=============
According to this article, CHANNEL STATUS=0 means that the line is
available: www.voip-info.org/wiki/view/channel+status

Here are extensions.conf, the AGI script, and what the CLI says:
=============== extensions.conf
[from_fxo]
exten => s,1,Wait(2)
exten => s,n,Set(CID=${CALLERID(num)})
exten => s,n,Wait(10)
exten => s,n,Hangup

exten => h,1,DeadAGI(/var/tmp/test.lua)
=============== AGI script
#!/var/tmp/lua
for i=1,10 do
        io.write("CHANNEL STATUS\n")
        response=io.read()

        _, _, key, value = string.find(response, "(%a+)=(%d+)")

        --Channel never "down and available"!
        if value=="0" then
                io.write("NOOP Channel idle\n")
                response=io.read()
        else
                io.write("NOOP Channel N.A.\n")
                response=io.read()
        end
        os.execute("/bin/sleep 2")
end
=============== CLI
...
AGI Rx << CHANNEL STATUS
AGI Tx >> 200 result=4
AGI Rx << NOOP Channel N.A.
AGI Tx >> 200 result=0
AGI Rx << CHANNEL STATUS
AGI Tx >> 200 result=4
AGI Rx << NOOP Channel N.A.
AGI Tx >> 200 result=0
...
=============== 

IOW, although I use Hangup() in extensions.conf and wait several
seconds before calling "CHANNEL STATUS", the channel is never marked
as "down and available".

Do I need to perform some extra steps in extensions.conf or in the
script for the FXO port to finally be available for a callback?

Thank you for any help.

On Fri, 18 Feb 2011, Gilles wrote:
> I'm using an AGI script in Lua to make a callback through Zaptel.
> =============== AGI script
> #!/var/tmp/lua
> for i=1,10 do
>        io.write("CHANNEL STATUS\n")
>        response=io.read()
>
>        _, _, key, value = string.find(response, "(%a+)=(%d+)")
>
>        --Channel never "down and available"!
>        if value=="0" then
>                io.write("NOOP Channel idle\n")
>                response=io.read()
>        else
>                io.write("NOOP Channel N.A.\n")
>                response=io.read()
>        end
>        os.execute("/bin/sleep 2")
> end
I'm just a 1.2 Luddite...

I've never written an AGI in lua, but don't you have to read the AGI 
environment (from STDIN) before issuing requests?

Also, you execute your AGI in the 'h' extension. I think once a channel
is
hung up, it's state will not change until you reach the end of your 
dialplan execution and the channel is destroyed.

I'm guessing you would have better luck kicking off an external process 
that checks the channel status via AMI.

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                              Fax: +1-760-731-3000