Product Review: S2USB485 Interface and S2USB485DiagN2 Utility

As part of our commitment to our Integration Partners and Distributors, we look for ways to improve the integration process and refine best practice recommendations. One such best practice that has been proven is validating the N2 bus - to make sure that it is in spec and that N2 devices are responding properly - before attempting an integration. We always include this discussion as part of our live demo and training sessions. We emphasize the fact that, with any integration to BACnet IP, the N2 bus will be driven harder than ever before. If any latent defects exist, you are guaranteed that they will be exposed. Following this process has saved our partners countless hours of labor and reduced risk on many projects by identifying and fixing N2 bus issues early in the process and in a controlled manner.

S2USB485Somehow, we have managed to find a group of partners who are not at all bashful about telling us where good things could be improved. We have frequently heard the request that they would like to be able to capture the results of the N2 bus validation. Those requests have gotten more frequent as our partners have taken on larger and more complex projects. We have found the answer in the S2USB485 adapter from S Squared Innovations. This is much more than a typical USB to RS-485 converter. Features include:

  • USB Port Powered
  • Included USB to RS-232 Converter
  • S Squared Innovations OBD (On-Board Diagnostics) of the RS485/N2 Bus
  • S2USB485DiagN2 Free N2 Bus Diagnostic Software
  • Compatibility with JCI Metasys┬« configuration and commissioning utilities


We tested both the S2USB485 adapter and S2USB485DiagN2 utility in our lab environment and both installed easily and worked flawlessly. The diagnostic software measures N2 bus voltages and provides a pass / fail assessment. Integrators can do a screen capture of the results which can be included in project documentation.

Another of our best practice recommendations is that our partners have a copy of the M-Tools available as part of their standard integration toolset. That typically means purchasing a USB to RS-485 adapter. The S2USB485 serves this purpose very nicely -- for the cost of a typical USB to RS-485 adapter you also have a very powerful diagnostic tool. Two of your first tasks when visiting a new project should be:

  1. Run the S2USB485DiagN2 diagnostics, and
  2. Run a HVAC Pro Action / Controller Information report

Combined, these two actions give you all of the information you need to get your Metasys® integration project off to a successful start.

During our product evaluation we had numerous discussions with Sam Saprunoff, president of S Squared Innovations. He shared his plans for enhancements to the S2USB485DiagN2 utility that will add significant new capabilities to an already very good product.

North American partners can purchase the S2USB485 from The S4 Group. Contact us for a price quote.


Click here to check out the ComBus Quick Tester, another handy diagnostic tool