There are no external interfaces on the Cisco Unity Express hardware (physically there is an FE interface port, but it is disabled in software and unusable)all access must pass via the host router. The only local access to the Cisco Unity Express system is therefore via the host router's console interface. Access to Cisco Unity Express (via the router's command-line interface [CLI]) is only possible by using the following command:
lab-2691#service-module
service-Engine x/y session
This command requires Enable mode on the router and is therefore protected by the router's enable password settings. Although there is also an "enable" mode in the Cisco Unity Express module CLI, it has no password capability.
This URL should help you:
http://www.cisco.com/en/US/netsol/ns340/ns394/ns165/ns391/networking_solutions_design_guidance09186a00801f8e31.html