[asterisk-users] documentation of DAHDI dial options

[Klaus Darilion]

Jared Smith schrieb:
> On Tue, 2009-07-07 at 15:42 +0200, Klaus Darilion wrote:
>> I am searching for the description of the available dialstrin options 
>> for the DAHDI channel (and also other channel types).
>>
>> I am not looking for outdated voip-info links, but for the authoritative 
>> source, e.g. something like "core show application Dial"
>>
>> Does such thing exists?
> 
> I don't think that such a thing exists.  The only ones I'm aware of are:
> 
> 1) Channel Groups.  
> 
> DAHDI/g1/5551212 dials 5551212 on the first available channel in group
> one, searching from lowest to highest
> 
> DAHDI/G1/5551212 dials 5551212 on the first available channel in group
> one, searching from highest to lowest
> 
> DAHDI/r1/5551212 dials 5551212 on the first available channel in group
> one, going in round-robin fashion (and remembering where it last left
> off), searching from lowest to highest
> 
> DAHDI/R1/5551212 dials 5551212 on the first available channel in group
> one, searching in round-robin fashion from highest to lowest.
> 
> 2) Distinctive ring
> 
> DAHDI/4r1 dials channel 4 (presumably an FXS channel), and uses
> distinctive ring style one.  If I recall, there are four different
> distinctive ring styles... so you could replace r1 with r2, r3, or r4.
> 
> 3) Answer confirmation
> 
> DAHDI/1c/5551212 tells Asterisk to dial 5551212 on DAHDI channel 1, and
> not consider the call answered until the called party presses #.  This
> is useful because of the way analog signaling works.  Without this
> setting, Asterisk considers any outbound analog call on an FXO port
> answered just as soon as it has been dialed.
> 
> 4) Digital calls
> 
> DAHDI/1d/5551212 tells Asterisk to dial 5551212 on DAHDI channel 1, and
> that it's a digital call.  If I remember correctly, this is used for
> ISDN calls to set the bearer capability.
> 
> I've taken a quick look in channels/chan_dahdi.c in TRUNK, and it seems
> to match up with my understanding, as I didn't see any other options
> stand out.  While poking around in there, I found the following comment:
> 
>         /*
>          * data is ---v
>          * Dial(DAHDI/pseudo[/extension])
>          * Dial(DAHDI/<channel#>[c|r<cadance#>|d][/extension])
>          * Dial(DAHDI/(g|G|r|R)<group#(0-63)>[c|r<cadance#>|d][/extension])
>          *
>          * g - channel group allocation search forward
>          * G - channel group allocation search backward
>          * r - channel group allocation round robin search forward
>          * R - channel group allocation round robin search backward
>          *
>          * c - Wait for DTMF digit to confirm answer
>          * r<cadance#> - Set distintive ring cadance number
>          * d - Force bearer capability for ISDN/SS7 call to digital.
>          */
> 
> That's probably as definitive an answer as you're going to get.

Thanks, great. So now we have what I was looking for.

Now we need a place to make this documentation public. I wonder what 
could be a place for that?

IMO it would be great if the documentation would be inside Asterisk. 
Maybe it could be added to "core show channeltype dahdi". What do you 
think? Otherwise this information is again lost, and voip-info pages are 
always outdated.

regards
klaus