TOPServer OPC Power Server
http://www.toolboxopc.com/

The TOPServer offers the widest choice of communications software written to the OPC standard. Backed by the engineering and support expertise necessary to support more hardware and your demanding application needs. Users, Integrators, and OEMs can all benefit from the savings our approach to OPC Server software delivers to you

Here are just some of the features & advantages of the TOPServer:

• Over 70+ drivers to choose from and use within the TOPServer.
• Dial-Up Modem Support in Serial Drivers
• Implement Redundancy from your client application to Switch COM ports, Switch Ethernet cards, Control a Modem, Change device ID or IP Addresses, Enabled/Disable a device, Change Timeout settings etc.
• Detect if a Device is online/offline via special system Tags
• Dynamic Tag Creation
• Extended functionality also allows you to specify data-type and scan-rate of a tag
• and much, much more...