Thank you ralph for pointing me in the right direction. After figuring out that you have to hold different keys to boot into different settings menus (which seems stupid to me, why not just have them all in one menu). I held the "7" key to boot to the Teleworker settings menu and cleared those present setting out. After that the phone was then able to contact the PBX (TFTP server), download and install the appropriate firmware and then connect to the system.