Just noticed a small problem with my setup, hope someone can see what I'm doing wrong.
After hours my FXOs go to a classic extension which contains the out of hours mobile phone number.
This works fine. However we just noticed today that a second simultaneous caller doesn't get a 'busy tone' as we had expected, but carries on with a 'ringing tone' which seemingly goes nowhere.
Note that the mobile doesn't have voice mail and no other system diverts are set.
My question is ... why doesn't the 2nd caller get a 'busy'
I believe the trunk used to call the Mobile number, doesn't properly support Carrier Announcements (183 Session Progress with SDP). Try using another trunk to deliver the call to the Mobile, and note the result.
If you enable the Call Waiting option on the mobile phone's Classic extension, will the second call be delivered properly to the Mobile phone?