[Asterisk-Dev] Does anyone have docs on the Q.931 "high layer compatibility" IE?

[Peter Svensson]

On Fri, 29 Oct 2004 steve at daviesfam.org wrote:

> We're interworking from Asterisk to a local, popular, PBX.
> 
> I've got a little patch or two for issues we had - which I'll put on bugs 
> shortly.
> 
> We've just got a very subtle issue left - digital phones on the PBX 
> display callerid "differently" when the calls come from Asterisk as to 
> when coming from the telco.
> 
> The PBX still gets the callerid and dnid fine, and presents them fine to 
> other ISDN interfaces - its just about the display on their proprietary 
> digital phones.
> 
> I think it has to do with Asterisk not including a "high layer 
> compatibility" IE in its call setup.  I see these coming from the telco, 
> but not generated by Asterisk.
> 
> Does anyone have docs on how this IE is structured and what it means (my 
> ISDN/SS7 book is not specific enough).

It is in the q.931 standard. You may be able to download it for free from 
ITU: http://www.itu.int/publications/bookshop/how-to-buy.html#free.

Peter