Before I started switching over a few lucky people to the new system, I needed to first set up a test platform. Setting up a test platform allowed me to confirm whether or not Cisco CME did support SIP trunking and RFC2833.  According to the documentation the current IOS that I had installed did support SIP trunking but did not support RFC2833. 

After finding out the current IOS did not support RFC2833, I contacted my SE and he then signed me up for their developer beta program.  Once the process was completed, I was able to download a beta IOS that did support SIP trunking and RFC2833.  I ran some test against the Asterisk voice mail system which required that I use a four digit PIN to enter my voice mail.  Doing this enabled me to test RFC2833 quickly.  I then did more tests to various other numbers that required me to input digits to the IVR systems.  I concluded that RFC2833 was viable and started to move to Stage 1 of my migration plan.

The migration to Stage 1   added the Asterisk server for voice mail for CME, Nortel PBX, two FXS ports, a T1 for backup, and routed all outbound calls via SIP trunking through the production network.  In bound calls to the Cisco CME are routed over a T1 that I cabled between the Nortel PBX and Cisco CME.  Currently I have 7 people using the CME and the rest are still on the Nortel PBX. Once IOS 12.3(14)T is released, which fixes bug CSCeg52696, I will implement Stage 2 of the migration plan.

The difference between Stage 1 and Stage 2 is the removal of the Nortel PBX T1 circuit, which is installed directly into the Cisco CME, everyone is moved to the IP PBX, and 24 FXS ports are installed.  Upon completion of the second stage, it will remain in service for a minimum of 30 days.  In the allotted time I would hope that 30 days will be enough to work out any unforeseen set up problems or bugs.  If one should arise that is server, I would convert back to the Nortel PBX until the problem is resolved.