If you choose to connect to your home server from another PC or phone, you can use the test feature and the access key (from MC Options > Media Network) for access to your home PC.
The port must be accessible (not blocked by a firewall) and you must use the outside address of your network. A cable modem, for example, has both an inside and an outside address. The outside address is the only one accessible from the Internet. You can find out what your outside address is by visiting whatsmyip.org.