I don’t think anyone has created a plugin for STNP that will work with a DSC panel yet. The Envisalink/DSC TPI uses a different set of codes from what is used for Envisalink/Vista. The TPI is well documented though, and redloro’s plugin structure is easy to work with. It should largely just be a matter of changing the codes that are sent/received and accounting for the checksum. The envisalink.js plugin would be a good base, though some changes to the logic might be necessary since my understanding is that the DSC panel provides better information to the Envisalink (most notably, notification when a zone clears).
However… I think most are using the following solution to integrate DSC panels with ST: