Altronix SMP7CTX Selectable 12/24VDC Power Supply
The Altronix SMP7CTX is a field-configurable power supply that solves a common retrofit problem: delivering the right voltage to mixed-generation security hardware from a single unit. Output is selectable between 12VDC or 24VDC, determined by a simple field jumper — no vendor callbacks, no spare inventory of voltage-specific models. Input range spans 12–28VAC, which accommodates standard transformer secondaries found in most commercial installations without requiring a separate step-up or step-down converter.
Key Features
- Selectable 12VDC or 24VDC output: Field-configurable via jumper eliminates ordering wrong-voltage spares. Change voltage once during commissioning or retrofit without replacing the unit.
- 10A @ 24VDC or 6A @ 12VDC: Sufficient capacity for typical access control readers, magnetic locks, and PTZ motor auxiliaries. At 24VDC, you get 240W; at 12VDC, 72W — useful context when sizing the transformer or estimating total panel load.
- Input range 12–28VAC: Works with 120V/24V or 120V/12V transformer secondaries, and tolerates AC supply sag without dropping offline. No separate voltage regulator needed upstream in most cases.
- Single output design: One set of terminals means simpler wiring than dual-output supplies. Reduces panel congestion and connector count.
- Compact form factor: Panel or DIN rail mount option keeps enclosure footprint minimal, important in crowded electrical closets and retrofit scenarios where space is already tight.
- Lifetime Limited Warranty: Manufacturer backs the unit for the life of the equipment, removing replacement cost from your spares budget after the initial purchase.
Integration & Compatibility
The SMP7CTX integrates into standard power infrastructure racks and panels wherever access control or surveillance auxiliary loads exist. Pair it with access control power supplies in mixed-voltage installations, or use it as the sole 24VDC source for a small PTZ camera array or a bank of card readers. Input sourcing is flexible: direct from a panel transformer, a UPS-backed secondary, or a field-installed step-down. The output is unregulated DC, so plan for 5–10% sag under full load if the upstream AC supply is weak.
When to Choose a Different Model
If your installation requires dual independent outputs (e.g., 24VDC for card readers on one rail and 12VDC for auxiliary sensors on another), evaluate a multi-channel variant in the Altronix power supply line. If you need integrated backup (battery backup for elevator phones or emergency locks), step up to a model with built-in charging. For installations exceeding 10A draw, you'll need a higher-capacity unit or parallel configuration.
Expert Commentary
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The SMP7CTX earns its place on retrofit jobs where you're mixing old 12V card readers with new 24V strikers and you don't want to run two power supplies. The selectable output jumper is the key win here — it means one SKU on the shelf covers both scenarios.
Technical Highlights:
- 10A @ 24VDC output: Handles four 2.5A magnetic locks or a PTZ camera array with pan/tilt load without undersizing. At 12VDC, 6A output maxes out around three larger solenoid devices before you need a second supply.
- 12–28VAC input window: Practical for field-installed transformers or existing panel secondaries that may sag slightly under load. Avoids nuisance shutdowns on borderline supply conditions.
- Lifetime Limited Warranty: Removes replacement cost after year one, a real factor when the unit is buried in a panel and labor cost to swap it exceeds the unit cost.
Deployment Considerations:
- Output is unregulated, so expect 5–10% voltage sag under full 10A load depending on input AC quality. If you're powering sensitive electronics (some older card controllers are finicky), test it under load or add a local regulator on the 24V rail.
- The jumper selection is field-side, but it's permanent once set — label the enclosure clearly so the next tech doesn't accidentally flip it during maintenance.
Deploy the SMP7CTX on mixed-voltage access control retrofits and small surveillance auxiliary systems where you want to avoid multiple supply units. It's not a backup power device, so don't use it for 24-hour emergency lighting or life-safety circuits that need UPS continuity.
Frequently Asked Questions
Q: Can I change the output voltage after installation?
A: Yes. The SMP7CTX is field-selectable via jumper. You can switch between 12VDC and 24VDC output without replacing the unit, but you'll need to power down and reconfigure connected devices to match the new voltage.
Q: What is the warranty on the SMP7CTX?
A: Lifetime Limited Warranty from the manufacturer. Labor and shipping are not covered under the warranty — that depends on your service agreement or distributor terms.
Q: Will the SMP7CTX work with a standard 120V/24V transformer?
A: Yes. The input range of 12–28VAC accepts 24VAC transformer secondaries, including those with some voltage sag under load. If your transformer sags below 12VAC, the unit will drop offline; oversized or low-impedance transformers are preferred.
Q: What's the maximum load I can draw from the SMP7CTX?
A: At 24VDC, 10A maximum (240W). At 12VDC, 6A maximum (72W). Plan your load budget accordingly; if you need more capacity, use a higher-amp unit or parallel configuration.
Q: Is the SMP7CTX suitable for backup power or UPS applications?
A: No. This is a line-powered supply with no built-in battery charging or backup function. For emergency or 24-hour life-safety loads, specify a model with integrated UPS or battery backup.
Q: What mounting options does the SMP7CTX support?
A: The unit is designed for panel or DIN rail mounting. Screw terminals accept 12–14 AWG wire for input and output connections.
