[asterisk-dev] Zap outofband busy indication to mobile networks

[Tristan Graham - Skymarket Ltd]

Hi folks,

Got an oddity that a user has raised to do with busy signalling and 
inparticular when calling from a mobile phone. It seems that the 
behaviour when calling * is slightly different to the norm i.e. If I 
call an engaged landline number directly from my mobile then the mobile 
gives engaged tone plus displays "number busy" then hangs up. If however
I call * and pass the call simply to "Busy" then I get either the 
regular engaged tones (priindication=inband) or three short tones 
followed by hangup (priindication=outofband). The latter is closest to
what normally happens but does not indicate busy as intended. I
initially thought this might be down to the fact its iSDN but I have
tried a similar test using a-n-other PBX on an iSDN 30 and that seems to
act normally. Landline caller receives engaged tone as expected.

Can anyone verify this behaviour and tell me if it is normal or bug
worthy ?

This is tested on asterisk 1.2.4, caller on UK mobile network and *
connected using Zap E1 direct to telco hardware with SS7 onto network.

Tristan.