[asterisk-users] how to avoid call waiting? Or check DIALSTATUS before Dial()?

[sean darcy]

sean darcy wrote:
> I have two internal analogue extensions off a TDM400P. If the first is 
> busy, I'd like to ring the second. So:
> 
> [incoming]
> exten =>s,1,Answer()
> exten =>s,n,Dial(${mainline},60)
> exten =>s,n,ExecIf($["${DIALSTATUS}" = "BUSY"]?Dial(${secondline},30))
> 
> But it doesn't work because * first tries Call Waiting on the main line. 
> Here I dial out:
> 
>      -- Starting simple switch on 'DAHDI/1-1'
>      -- Executing [140 at internal:1] Answer("DAHDI/1-1", "") in new stack
>      -- Executing [140 at internal:2] Set("DAHDI/1-1", "CALLERID="house" 
> <2127873453>") in new stack
>      -- Executing [140 at internal:3] Dial("DAHDI/1-1",
> .............................
> 
> And now an incoming call:
> 
>      -- Executing [s at incoming:1] Answer("IAX2/nhi-10929", "") in new stack
>      -- Executing [s at incoming:2] Dial("IAX2/nhi-10929", "DAHDI/1,60") in 
> new stack
>      -- Called 1
>      -- IAX2/nhi-10929 requested special control 20, passing it to DAHDI/1-2
>      -- IAX2/nhi-10929 requested special control 20, passing it to DAHDI/1-2
>      -- IAX2/nhi-10929 requested special control 20, passing it to DAHDI/1-2
>      -- DAHDI/1-2 is ringing
>      -- IAX2/nhi-10929 requested special control 20, passing it to DAHDI/1-2
>      -- IAX2/nhi-10929 requested special control 20, passing it to DAHDI/1-2
>      -- CPE supports Call Waiting Caller*ID.  Sending 'Seandarcy/212 573 
> 1432'
> 
> 
> Is there a way to check the status of a dahdi channel _before_ dialing it?
> 
> exten =>s,n,ExecIf($["DAHDI/1${DIALSTATUS}" = 
> "BUSY"]?Dial(${secondline},30)) ??
> 
> What's special control 20  ??
> 
> Any help appreciated.
> 
> sean
> 

BTW, this is on 1.6.1.

sean