ADO connection to Progress OpenEdge database in Visual Studi

(I am a rank noob working with OpenEdge. So if I ask something dumb, please correct me. [:D])

I am working on determining how to connect to an existing OpenEdge database that is used with my company's application. I am working on options for connection to the database outside of our standard development environment for the purpose of testing. So I want to start with creating a basic connection using ODBC in ADO. Using articles I found in the knowledge base, I have a class that looks like:

using ADODB;
using System.Data.Odbc;

namespace VSIAutomationDataManager
{
    public class DataTools
    {
        private string connectionString()
        {
            string myString =
                "DRIVER=Progress OpenEdge 11.7 Driver;HOST=QA2-W2012R2-TC;PORT=4003;DB=RecTrac;UID=zzz@VSI;PWD=password;DIL=Read Uncommitted";
            //string connString = "DRIVER=Progress OpenEdge 10.2B Driver;HOST=localhost;PORT=9999;DB=sports2000;UID=pub;PWD=pub;DIL=Read Uncommitted".

            return myString;
        }

        public void MakeConnection()
        {

            OdbcConnection cn = new System.Data.Odbc.OdbcConnection(connectionString());
            cn.Open();

        }
    }
}

I receive the error

"Data source name not found and no default driver specified"

when executing the cn.Open(); command from my unit test that exercises this poor, boring class. 

I am attempting to do a DSN-less connection. 

Any words of wisdom as to what I might be doing wrong, please? Thanks!

Stephanie