IMEI: 357937004286177 Country: Australia Provider: Optus (also used on Telstra) Firmware: V04.50 19/12/05 RM30 This is a weird one. The phone only locks with a "phone restricted" (enter restriction code) after it has been sitting idle for several hours. If I then reboot the phone, it works okay again for another few hours. If I put the same SIM card in another working phone, the same thing happens after several hours. Optus issued a new SIM with the same number.. same problem. Changed unit with a brand new phone (same phone number), same problem. Used a different Optus SIM/phone number, NO problem. Unfortunately I need to keep this phone number in service. Anyone seen this before?