When a 7912 phone, receives a call (handset goes OffHook), then proceeds to execute the Call-Park feature successfully (call gets parked), then puts the hand-set back to go OnHook. However, the next time this 7912 phone goes OffHook with the handset (thus, placing a call)......the 7912 phone automatically reboots (sometimes we get as far as dailing two buttons before the reboot). This is a consistent problem with any of the 7912 phones used in our environment. Our environment consists of both 7912 and 7961 phones. The 7961 type phones do not have his problem.
In working with the Cisco TAC, we have tried different versions of the router IOS and CME versions. As well as, different 7912 phone loads.
The current IOS running on the 2811 router is v12.4(22)T4 and CME v7.0(1). The 7912 phone load is v8.0x.
(Take note, a packet capture via Wireshark was provided to the TAC, thus was sniffed from the ethernet port of the 7912 phone - Not enough relevant information to act upon in terms of a resolution). Lastly, TAC is unable to find any bug information about this problem.
Interestingly, I did downgrade the 2811 router to IOS v12.4(11)T3 with CME v4.0(2) and the problem stopped. However, this is NOT the solution because, this IOS & CME version DOES NOT support the Cisco Wireless 7925 IP Phones in our environment.
Other phone features on the 7912, such as; Transferring a call or Forwarding a call, works fine.
We are open for additional assistance. Thanks!!