Check the settings under:
External Line > Advanced Settings > Caller ID
The default in 1.20 is to perpend 9 before the number. I have no idea why it does that, it is actually quite annoying.
Especially considering there are very few caller ID services or locations where you would need to add 9 to the beginning of every number. It is possible the development team was using it to distinguish between internal extensions and external lines, but this shouldn't be automatically set for end users.
