DO i want to install Expressway C and E for registration.
do you have any link for this preocess.
what will be the TFTP ip it will take.
phone model: 7940 and 7942
None of those models support MRA, the 7942 supports phone VPN, but not the 7940.
Your best option would be a VPN from the remote site to CUCM so both models can work.