Simplex 4100-3109 — IDNet 2 interface module, 250 points per loop, two loops.The 4100-3109 adds addressable device capacity to a Simplex 4100ES fire alarm control panel. It provides two electrically isolated signaling line circuits, each supporting up to 250 addressable points, for a total of 500 points from a single module. Both loops can be wired Class A or Class B, so the module suits new installations and expansions of existing risers alike.Short-circuit isolation is built in, which keeps a wiring fault on one segment from taking down communication across the whole loop — the practical difference between a localized trouble and a system-wide outage. It occupies one block space in the panel, and works with the full range of Simplex addressable devices: detectors, manual stations, monitor and control modules, and notification appliances.Confirm available block space and panel firmware revision before ordering.