[asterisk-dev] ISDN Cause Code 100, Bosch Integral Management Connection

Michael Neuhauser mike at firmix.at
Fri Nov 7 02:53:08 CST 2008

On Mit, 2008-11-05 at 09:42 +0100, Wolfgang Pichler wrote:
> Hi all,
> we have the following setup
> PSTN 3 PRI Lines   <--->  Asterisk (1.4.22)   <--->  Siemens  HiCom   
> <--->   Bosch Integral
> The Asterisk Machine does play the man in the middle - and adds some 
> extra functionality to the system (SIP users...) - the normal calls are 
> getting 1:1 through the system (incoming calls from PSTN are handled by 
> a simple Dial(ZAP/g1/${EXTEN}) (g1 = Siemens side) - so no special 
> handling here...
> Everything is working as it should - beside of one little thing. The 
> Bosch Integral PBX does have a special extension (99) which is used to 
> remote manage the machine - this managment connection is working fine 
> without asterisk, as soon as asterisk is connected in the middle the 
> management connection wont work any more - getting back isdn cause code 
> 100. I have already tried dial options d und c (make it digital - clear 
> channel) - no success.

Cause 100 is 'invalid IE contents'.

This part of the outgoing SETUP

> [Nov  5 08:49:22] VERBOSE[1815] logger.c: > Bearer Capability (len= 5) [Ext: 1  Q.931 Std: 0  Info transfer capability: Unrestricted digital information (8)
> [Nov  5 08:49:22] VERBOSE[1815] logger.c: >                              Ext: 1  Trans mode/rate: 64kbps, circuit-mode (16)
> [Nov  5 08:49:22] VERBOSE[1815] logger.c: >                                User information layer 1: Unknown (63)

looks wrong to me: the value of the User information layer 1 (63 = '11
1111') is a reserved value. Furthermore, the Q.931 standard says:

        If the transfer mode is “circuit mode”, and if the information
        transfer capability is “unrestricted digital information”
        or “restricted digital information”; and if the user information
        layer 1 protocol is to be identified only to the addressed
        octet 5 shall be omitted.

This seems to apply to the given problem (but I'm not 100% sure how
"and .. is to be identified only to the addressed entity" is to be

So maybe the Siemens PBX does not like the presence of the user
information layer 1 protocol octet or the specific value. It would be
interesting to see the original SETUP from the PSTN, especially if it
contains a User information layer 1 protocol octet.

Dr. Michael Neuhauser                              mailto:mike at firmix.at
Firmix Software GmbH                                  sip:mike at firmix.at
Vienna/Austria/Europe                               tel:+43-1-7890849-30
Linux Development and Services                     http://www.firmix.at/

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