How are the dSMs and the dSS connected? digitalSTROM Support September 28, 2018 06:12 Updated Follow dSMs and dSS are connected via a 2-wire bus on which the dS485 protocol runs. Related articles Can I use a free NYM cable or control line for the dS 485 bus? What is the maximum cable length for a dS485 bus? A dSM does not respond although the LED is on Is the dSM equipped with surge protection?