[asterisk-dev] Overlapped dialling on SIP trunks for outgoing calls

[Johansson Olle E]

25 apr 2008 kl. 16.44 skrev Andreas Brodmann:

> 2008/4/25, Kevin P. Fleming <kpfleming at digium.com>: Andreas Brodmann  
> wrote:
> > After chasing a problem I looked at the SIP code (1.4.19)
> > with a colleague and as far as we understood it, overlapped
> > dialing on sip trunks for outgoing calls is not supported (yet?).
>
>
> in sip.conf you can set 'allowoverlap=yes'
>
> If a phone is configured accordingly (early dial) it will send an  
> INVITE request
> for each key a user presses. e.g. 1 at asterisk, 11 at asterisk and then  
> 111 at asterisk.
> For each incomplete INVITE asterisk will return 484 "Number  
> incomplete" until the
> client sends a number which is complete (e.g. matches a pattern).
>
> This works fine until a client tries to call a number that asterisk  
> reaches via a sip trunk to
> another pbx (or carrier), whereas the length of the number is unknown:
> // e.g. International Calls
> e.g. exten => 000!,1,Dial(SIP/${EXTEN:1}@carrier,120)
>
> in this case, asterisk will send an INVITE to the carrier after the  
> first 3 zeros. The answer
> from the carrier will be 484 (number incomplete). Instead of  
> forwarding this response to the
> phone asterisk will end the call -> congestion.
>
That's another issue. Outbound overlap dialling is something that is  
propably not implemented.
That will require a lot of coding I think, but other developers might  
understand overlap dialling
*through* asterisk better.

For PRI, I believe we put the call in UP state and then simply forward  
dtmf...

/O