CONNECT system/mypassword@mydbserver.mydomain.com:1522here is an eg... more have here download.oracle.com/docs/cd/B25329_01/doc/admin.102/b25107/connecting.htm
Rdf = (description = (address_list = (address = (protocol = tcp)(host = remoteserver)(port = 1521)) ) (connect_data = (service_name = localname) ) )