Using the following ConnectionString, I get an InvalidOperationException that says "UnknownConnectionStringParameter":
"User Id=username;Password=password;Direct=true;Data Source=server.domain.com;Port=1521;SID=ORCL"
Help? This is version 3.50.12.1 of the Mobile edition that I just downloaded today, and the platform is a Symbol Technology MC9090-G running Windows Mobile 5. I get the same error whether I use the fully qualified name of the server or it's IP address.