We have just taken over a 3300, user has a 4025 phone and when she is on a call if a second call comes in a light flashes to alert her but she would prefer the second caller to get busy tone.
Pointers please on where to look in the programming.
Thanks

Just to add that the first alternative for 'Busy DID' on that extension is set to normal.

Delete the second multiline so that the prime is a single line. You will need to check the rerouting and forwarding to ensure the caller doesn't follow one of those routes.

Just been on site to test, when a second call comes in on the users extension 'Waiting' appears in the display and 'Trade' option appears above one of the soft keys.
Line type is set to single.

I believe you will need to turn off call waiting in her class of service (I'd make a distinct class for her).

Thanks for that pointer, I have been right through all the COS options and I can't see Call Waiting, is it called something else on a Mitel.

In the Mitel it would come under the Camp On timer. When you are in the form and hit the help button on the top right it will open up a new screen that explains the options.

Thanks for that Steve, it was the COS/Auto Camp-On Timer for the Trunk, field needs to be blank.