Message Status affecting phones

We have a small asterisk setup, with various extensions running with a TDM410 as the primary outbound.

On the landlines, we have some call forwarding, setup if either is busy etc, which means the dialtone on those lines is different (i.e. the same as if you have a message on 1571).

This is being passed through to the extensions on the PBX, and I can’t work out how, or even how to remove it? The extensions are a combination of FXO and SIP extensions.

The command line output that changes it is:
“Message status for changed from -1 to 1”

Anyone any ideas?

Thanks
Nunners

Is there anyway of setting the dialtone on extensions not to pickup the dialtone on the outside line?