Which version (platform) is the Cisco Call manager installed onto? Technically, you should be able to run a call manager server, connected to a hub, and hook up the 2 phones and they can call each other. However, there are potential limitations…
1. Phones need to be powered. Got a hub/switch to provide PoE (power)?
2. Got a DHCP server for the phones to get IP addresses? And provide the DHCP 150 option to point to the TFTP service on the Call manager server?
3. Done ALL the configuration on the Call manager, including loading licenses, identifying all the phones, dialing pools, patterns, etc.
4. Realizing you don’t get to the outside world without a proper gateway or trunk connection?