I am sorry, I almost always verify the info before I post but didn't this time, I relied on what was told to me.
It is actually an NEC NEAX 2000 IPS with an NEAX Mail AD64 voicemail.
The extensions do start with 9, 8 is used as outgoing. All of the phones in this department ring when extension 9755 receives a call, the phones do have a Station Line key for 9755, I have tried to remove the Station Line key for 9755 but the phones still ring when a call is placed to 9755.