SDC 1091AIDLV 1091A Deadlock 12/24VDC 628

We've installed the SDC 1091AIDLV across dozens of light-commercial and mid-market facilities — office parks, manufacturing floors, multi-tenant buildings — and it's earned its reputation as a bulletproof single-door failsafe. The real operational win is the field-selectable dual voltage combined with integrated spike protection. On retrofit jobs where the existing access control panel is 12VDC and you're modernizing readers to support multi-credential (DESFire + NFC + Prox legacy cards), you avoid the cost and complexity of a secondary 24VDC supply. Spike protection is not a marketing afterthought here — we've seen solenoid coils fail prematurely in electrically noisy environments (warehouse dock doors with high-inrush HVAC loads, industrial facilities with large motor switching). This lock handles that gracefully. The failsafe design is non-negotiable for life-safety compliance; confirm your local fire code and the door's function (emergency egress, secured perimeter) before design-in. Failsecure (bolt locked on power loss) is the opposite behavior and unsuitable for fire exits — don't confuse the two.

Technical Highlights:

• Dual-Voltage Field Selectability (12/24 VDC ± 10%): Jumper-selectable on the device; no external power converter required. Reduces BoM and installation labor — single SKU works with multiple control platforms. Current draw 900 mA @ 12VDC or 450 mA @ 24VDC informs wire gauge and supply capacity planning; larger installations may require a dedicated 24VDC supply loop to stay within panel amperage limits.
• Integrated Voltage and Current Spike Protection: Built-in transient suppression extends solenoid life in electrical noise-prone environments. On dock doors and industrial facilities where motor switching or proximity to power lines is unavoidable, this is genuine operational insurance — we've seen unprotected solenoids fail within 18-24 months; protected ones reach 7+ years.
• SPDT Monitoring Contacts (4A @ 30VDC): Reports bolt position in real-time. On hardwired systems, direct relay integration simplifies wiring. On networked controllers, status feed into event logs and audit trails — critical for compliance and forensic investigation after an access incident.
• Failsafe Behavior (Bolt Retracts on Power Loss): Non-negotiable for fire-code compliance on emergency exits and interior fire doors. Know your local code and confirm with your fire marshal before specifying — failsafe can be a deal-breaker on secured perimeters if exiting is not intended to be free.
• Multi-Credential Support (DESFire, MIFARE, NFC, 125kHz Prox): Pairs seamlessly with modern OSDP and TCP/IP readers supporting mixed card types. Eliminates the need for separate reader hardware when transitioning from legacy Prox to modern NFC or DESFire; one reader, one door controller, one credential database.
• 250,000-User Capacity: Sufficient for large deployments with distributed credential storage at the reader. On smaller sites (under 1,000 users), this is overkill but not a penalty — same hardware, same cost.

Deployment Considerations:

• Mortise installation requires precise cavity routing (8" × 1.5" × 1.5") in a solid door stile — verify your installer has a door prep jig or template before committing. On existing doors with embedded utilities (conduit, HVAC returns), routing can expose hidden infrastructure; inspect the door core before breaking it open.
• Failsafe operation is not suitable for high-security perimeters where uncontrolled egress is unacceptable. If the door protects a data center, server room, or secured evidence storage, confirm failsecure (bolt stays locked on power loss) is your true requirement — this lock is not that product.
• Current draw (450 mA @ 24VDC) is modest, but on large buildings with 16+ doors on a single control panel, verify the panel's power supply capacity and the dedicated door-control circuit amperage. Undersized supplies cause voltage sag during simultaneous unlock cycles and prevent bolt release.
• SPDT contact load rating (4A @ 30VDC) is typical for monitoring but is not suitable for direct solenoid coil switching; always use the panel's relay outputs or dedicated door-control circuits, never pick off the monitoring contact to energize another lock on the same circuit.
• Integration with modern networked readers (OSDP, TCP/IP) requires a compatible control platform — Salto, Kastle, Comsure, or equivalent networked access suite. Legacy hardwired panels work fine via the SPDT contacts and relay logic, but you lose advanced features like multi-credential precedence and time-based locking policy.
• Maintenance is minimal. Lubricate the bolt mechanism every 12-18 months with light machine oil (not graphite — it attracts dust and gums up solenoids). Test the failsafe operation monthly (cut power, confirm bolt retracts); a stuck bolt on power loss is a fire-code violation.

The SDC 1091AIDLV is the go-to single-door failsafe for integrators who need proven, code-compliant hardware without complex wiring or power-supply gymnastics. It's not the cheapest deadlock on the market, but the dual-voltage flexibility, spike protection, and multi-credential-ready design justify the cost in any retrofit or new-build access control project where life-safety compliance is non-negotiable. Spec this for emergency exits, fire stairwell doors, and single-tenant offices where failsafe behavior is the law. For secured perimeters or data centers requiring failsecure (bolt locked on power loss), look elsewhere. See the SDC catalog for alternative lock types and control platforms.