This way you can connect the system to other phone. View and Download Mitel 5312 administrator's manual online. I have to replace someones phone on a Mitel 3300 and we just took over this system so a bit new to us. Mitel and its affiliates and subsidiaries assume no responsibility for any errors or omissions in this document. The password must be longer than five characters. MIVB Busy reset locked extension To reset a mailbox password follow the steps below: Log in to your system as far as the first screen. Must not contain repeating digits such as '11111', '22222', etc. This changes your Mitel/Office 365 password. I need to reset the password on the Mitel superset 4025 from a previous employee Read full answer Be the first to answer 8:25:38 PM Mitel 3300 reset system password mitel 3300 reset system password And those ph … read more To install the 3300 ICP system: 1.