[Asterisk-Users] Re: Ringing indication not working as expected

[Sebastian Kayser]

* Sebastian Kayser <mls+asterisk-users at skayser.de> wrote:
> * Sebastian Kayser <mls+asterisk-users at skayser.de> wrote:
> > are there any caveats regarding ringing indication with Asterisk?
> PSTN <-- 3 x BRI --> POTS (NEC) <-- 3 x BRI --> Asterisk
>                       ^                             ^ 
>                       |                             |
>                 POTS telephone sets              snom SIP phones
> 
> With no options set in the Dial command, i.e. Dial(Zap/g2/<number>,60),
> the ringing behaviour is as follows.
> 
> - snom -> snom - OK
> - snom -> POTS telephone set - OK
> - snom -> PSTN - NOK
> 
> OK = ringing is signalled to the calling party as soon as Asterisk
> indicates it on the console (... is ringing).
> 
> NOK = no ringing is signalled to the calling party _although_ Asterisk
> indicates it on the console.

I gave "brig debug span 1" a try and it led to the following obvious
difference (sorry for the long lines).

snom -> POTS telephone set:
1 < Message type: ALERTING (1)
1 < [1 181  011  891 ]
1 < Channel ID (len= 3) [ Ext: 1  IntID: Implicit, Other Spare: 0, Exclusive Dchan: 0
1 <                        ChanSel: B1 channel
1                          ]
1 < [1 1e1  021  811  811 ]
1 < Progress Indicator (len= 4) [ Ext: 1  Coding: CCITT (ITU) standard (0) 0: 0   Location: Private network serving the local user (1)
1 <                               Ext: 1  Progress Description: Call is not end-to-end ISDN; further call progress information may be available inband. (1) ]

snom -> PSTN telephone:
1 < Message type: ALERTING (1)
1 < [1 181  011  891 ]
1 < Channel ID (len= 3) [ Ext: 1  IntID: Implicit, Other Spare: 0, Exclusive Dchan: 0
1 <                        ChanSel: B1 channel
1                          ]
1 < [1 1e1  021  821  881 ]
1 < Progress Indicator (len= 4) [ Ext: 1  Coding: CCITT (ITU) standard (0) 0: 0   Location: Public network serving the local user (2)
1 <                               Ext: 1  Progress Description: Inband information or appropriate pattern now available. (8) ]

So its:

    Location: Private network serving the local user
    Call is not end-to-end ISDN; 
    further call progress information may be available inband.

which works vs.

    Location: Public network serving the local user
    Progress Description: Inband information or appropriate pattern 
    now available.

which doesn't work. What's causing Asterisk to indicate ringing to the
caller in the first place but not in the second place? Is this regular
behaviour? Is there any way to also indicate ringing for snom -> PSTN
telephone calls?

- Sebastian