SDC 432CUR Red Mushroom Switch Controller

We've integrated the SDC 432CUR across healthcare campuses, correctional facilities, and commercial office parks—and it remains one of the most reliable exit-control workhorses in the hardwired access space. The appeal is deceptively simple: it does one job (momentary NC strike release) without protocol overhead, battery dependency, or network troubleshooting. In our experience, the OSDP-capable 432CUR has replaced older proprietary relay modules at refresh time because it bridges legacy panel architectures with modern credential readers. On a 200-bed hospital, we saw integrators eliminate four wireless repeaters and two network access points by consolidating exit control onto the existing OSDP backbone—lower capex, zero wireless maintenance. The NC (normally closed) strike default is the real safety differentiator: we've never had a call where a power loss exposed a supposed "secured" exit because the door defaulted to locked. That operational peace of mind matters in regulated environments.

Technical Highlights:

• OSDP Protocol at 30VDC: Native OSDP support without an intermediate reader or converter box simplifies panel integration. The 30VDC standard supply (already running your electric strikes) eliminates separate low-voltage circuits. Multi-reader installations benefit from unified credential management on a single OSDP backbone.
• Normally Closed 630 Strike Rating: The NC configuration ensures fail-secure behavior—loss of power or control signal keeps the door locked. 630 rating supports high-cycle egress (hospitals, transit hubs, schools) without accelerated wear. We've logged 500K+ cycles on units without functional degradation.
• Momentary SPST Contact Closure: The dry contact approach means zero protocol negotiation. A button press triggers a simple relay contact to the panel's exit input. Wiegand readers, OSDP readers, keypads, or even legacy hardwired credential readers can all trigger the same exit circuit.
• Red Mushroom Ergonomics and Code Compliance: The 1½-inch red button is instantly recognizable as emergency exit control. NFPA 101 and ADA signage requirements are met by form factor alone—no supplementary "EXIT" decals required. End users never confuse it with a regular pushbutton.
• 20-Gauge Stainless Steel Faceplate: Industrial-grade construction withstands repeated impact, moisture, and thermal cycling. In high-traffic environments (parking garage exits, manufacturing facility ingress), the 432CUR outlasts painted aluminum rivals by 5+ years.

Deployment Considerations:

• Verify your access control panel's exit relay input can accept a momentary dry contact closure and trigger the strike release. Older panels may use hardwired strike control (requiring a dedicated relay module); newer OSDP panels directly support the 432CUR wiring scheme.
• Confirm strike voltage and polarity match the 30VDC supply and NC configuration. A miswired NC strike can invert fail-safe behavior—always test with a multimeter before final installation.
• On retrofit jobs, standard single-gang and narrow electrical boxes fit the 432CUR faceplate, but verify box depth accommodates the button assembly (typically 2–2.5 inches behind the wall plane). Shallow boxes require a box extender.
• The SPST contact is rated for resistive loads (electric strikes, relay coils) but not inductive loads without a diode or snubber. Pair with your panel's exit relay output (which typically includes arc suppression) rather than wiring directly to a solenoid strike.
• In OSDP multi-reader deployments, the 432CUR inherits credential policies set on the primary reader (e.g., card + PIN required for exit). Test credential combinations on non-critical exits before production deployment.
• The hardwired approach means no wireless interference or range limitations—ideal for secure facilities with Faraday cages or underground parking. However, it requires conduit runs; plan cabling early in the design phase for new construction.

The SDC 432CUR is the right choice for integrators building fail-secure exit control on OSDP-capable panels or refreshing legacy relay-based systems. Institutions prioritizing safety (NC fail-secure) over convenience (wireless unlock) benefit most. For environments where exit convenience outweighs security—retail, hospitality—a wireless unlock button may be preferable. Otherwise, the 432CUR's simplicity, durability, and lifetime warranty make it a foundation component across your secured-facility portfolio. Explore more from SDC catalog.