ODBC Connections

I have a MS Access 2003 front end linked to MS SQL Server 2005 back-end remote. Several users access the program with a Nextal PC-Card internet access. If there is little of no activity, the pc-card will close the connection. I recently noticed that when I make a change to an underlying table like ‘Vendors’ the subform linked to the form ‘Purchase Order’ will update immediately. This tells me the connection is open and current just like it would if it was a true desktop database. I have been unsuccessful with change the pc-card operation and am looking for a way to do it in the code to close and open the connection like .NET technology in C#. Any ideas would be a great help.

Thanks in advance.