[Asterisk-Users] Dial Command Reference for SIP channel

[Chris Hastie]

On Fri, 12 May 2006, Dave Morrow <david.morrow at autodata.net> wrote
>Hi all.  I was reading a sample config someone had posted relating to
>call forwarding, and in it, they use a Dial command with components
>that I cannot find any reference to.
> 
>Can someone point me to a reference which could explain the difference
>between Dial(SIP/100|20|Ttr,,wW) and Dial(SIP/100,,wW)
>Specifically, what is the |20|Ttr ?  I cannot seem to find any
>reference which would indicate this is even a valid format for the SIP
>channel.

Well to my inexpert eye it looks wrong. Are you sure about the those 
stray commas in the first example?

Arguments can be separated by either a comma (,) or a pipe (|). So in 
your first you are dialling the SIP/100 with a 20 seconds timeout. 
What's left I think should be TtrwW, not Ttr,,wW. These are the 
'options' and are as listed at
http://www.voip-info.org/wiki-Asterisk+cmd+Dial. So if you loose those 
rogue commas, the answer to your "what's the difference" question is a 
specific time out value, the ability for both parties to perform 
transfers and a ringing tone.
-- 
Chris Hastie