I think I have resolved this
After spending hours reading numerous posts on the web, I found that if I create a ‘dial profile’ and set it like this
And use this dial profile in the Trunk as the dial profile instead of ‘default’
Then I get the Brr Brr ringing sound when an extension dials out.
If I set ‘Ringing Tone’ to ‘YES’ then I get the 1 second single tone, then 1 second silence ringing tone.
Tony