Vertiv PSI5-1000RM1201UN 1000VA 1U Rack-Mount Line Interactive UPS
The PSI5-1000RM1201UN is a 1000VA/900W, 1U line-interactive UPS built for rack environments where space is at a premium and power quality actually matters. With a 0.9 power factor, pure sine wave output on battery, and a bundled IS-UNITY-SNMP card, it bridges the gap between bargain-bin ferroresonant units and full double-conversion systems — making it a realistic fit for edge data closets, IDF racks, network equipment rooms, and security head-end racks running sensitive switching or NVR loads. The rackmount UPS category is crowded, but the PSI5-1000RM1201UN earns its place by pairing that high power factor with a management card that most 1U competitors charge extra for.
Key Features
- 1000VA / 900W at 0.9 Power Factor: A 0.9 power factor means you actually get 900W of usable real power out of that 1000VA nameplate — not the 600–700W you'd see from a 0.6-PF legacy unit. For a fully loaded edge rack with a managed switch, NVR, and a couple of IP encoders, that headroom matters.
- Pure Sine Wave Output on Battery: When utility power drops and the UPS transfers to battery, it produces a pure sine wave — not the stepped approximation (simulated sine) cheaper units generate. Active PFC power supplies in servers, managed switches, and modern NVRs require a true sine wave to stay stable on battery; simulated sine causes audible whine or outright instability in active-PFC loads.
- Line Interactive with AVR: The line-interactive topology continuously corrects over- and under-voltage without switching to battery, which extends battery life and keeps connected equipment stable during utility sags and swells. For sites with inconsistent grid quality — older industrial buildings, remote edge sites — this is more useful than a basic standby (offline) topology.
- 5 Total Outlets / 2 Programmable: Five 5-15/20R-compatible outlets give you enough ports for a typical 1U head-end build. Two outlets are programmable — you can configure sequential load shedding or timed restart sequences for specific equipment, which is useful when rebooting in a specific order matters (switch before NVR, for example).
- Bundled IS-UNITY-SNMP Card (RDU120): An SNMP management card ships in the box — this is not an optional add-on. That card enables remote monitoring of UPS status, runtime estimates, alarm thresholds, and graceful server shutdown via network management software. For unattended edge sites or distributed security infrastructure, remote visibility into UPS health is the difference between a planned maintenance window and an emergency call.
- Compact 1U Form Factor: A single rack unit means it fits in constrained IDF or security head-end enclosures without displacing switches or NVR appliances. 1U UPS units are always tight, so verify your rail depth before ordering.
- 120V Input/Output: Configured for North American 120V infrastructure — no step-down transformer needed for standard US rack environments. Confirm input voltage compatibility before deploying in international or dual-voltage sites.
Integration and Compatibility
The bundled SNMP card integrates with standard network management platforms that support UPS SNMP MIBs, including most enterprise NMS tools and VMS platforms that support power monitoring. The IS-UNITY-SNMP card supports graceful shutdown signaling, which means NVR and server software can be configured to save state and shut down cleanly before the battery is exhausted — critical for preserving recorded footage and database integrity. The programmable outlets also support integration with physical security controllers that can trigger outlet cycling on command. Review your VMS or NVR vendor's UPS integration documentation to confirm SNMP MIB compatibility with the Liebert PSI5 before deployment on a managed site. The PSI5-1000RM1201UN is part of Vertiv's Liebert UPS line, which includes extended battery module (EBM) options for sites needing runtime beyond what the internal battery provides — check the PSI5 product family for compatible EBM SKUs.
Frequently Asked Questions
Q: What is the actual watt capacity of the PSI5-1000RM1201UN?
A: The PSI5-1000RM1201UN delivers 900W of real power output, thanks to its 0.9 power factor on a 1000VA nameplate. This is meaningfully higher than UPS units with 0.6 power factors, which would yield only 600W from a 1000VA rating.
Q: Does the PSI5-1000RM1201UN produce a pure sine wave on battery?
A: Yes. When operating on battery, the PSI5-1000RM1201UN outputs a pure sine wave. This is required for loads with active PFC power supplies, including most modern servers, managed switches, and NVR appliances. Simulated sine wave UPS units can cause instability or audible noise with these load types.
Q: Is the SNMP card included or a separate purchase?
A: The IS-UNITY-SNMP card (also referenced as the RDU120 card) is included with the PSI5-1000RM1201UN — it ships in the box. You do not need to purchase a separate communication card for basic SNMP monitoring and graceful shutdown functionality.
Q: How many outlets does the PSI5-1000RM1201UN have, and are any programmable?
A: The unit has 5 total outlets. Two of those outlets are programmable, allowing you to configure load shedding sequences or timed restarts for specific connected devices independently of the other outlets.
Q: What rack space does the PSI5-1000RM1201UN require?
A: The PSI5-1000RM1201UN occupies 1U (one rack unit) of vertical space. Verify your rack's usable depth against the unit's physical dimensions before installation, as 1U UPS units can be depth-sensitive in shallower wall-mount or compact enclosures.
Q: Is the PSI5-1000RM1201UN compatible with extended battery modules for longer runtime?
A: The Liebert PSI5 product family supports external battery module (EBM) options. Confirm the specific compatible EBM SKU with Vertiv's product documentation for the PSI5 series before purchasing, as EBM compatibility is model-specific.
The spec that changes the deployment math on the PSI5-1000RM1201UN is the 0.9 power factor. On paper, '1000VA' sounds like the same box everyone else sells — but at 0.9 PF you're drawing 900W of usable real power, not 600W. For a security head-end rack running a 16-channel NVR, a PoE switch, and a handful of IP encoders or access control panels, that's the difference between a UPS that actually covers your load and one that trips into overload the first time you add a device.
Technical Highlights:
- Pure Sine Wave on Battery: Active-PFC loads — which describes nearly every modern managed switch, NVR, and server power supply — need a true sine wave when utility power drops. The PSI5-1000RM1201UN delivers one; units that output stepped approximations will cause instability or noise on these loads.
- Bundled IS-UNITY-SNMP Card: The RDU120 SNMP card ships standard, not as a $150–200 add-on. For distributed security infrastructure with unattended edge sites, that card is what enables remote runtime checks, alarm notifications, and graceful NVR shutdown before battery exhaustion — protecting recorded footage.
- 2 Programmable Outlets: Sequential load shedding matters when your NVR needs the switch up before it can write to disk. Program the outlets to bring the switch up first, then the NVR, and you avoid file-system errors on reboot after a power event.
Deployment Considerations:
- Line-interactive topology corrects voltage sags and swells without switching to battery — this extends battery life significantly on sites with dirty utility power, which describes a lot of older industrial and warehouse facilities. Budget for battery replacement cycles regardless; line-interactive batteries still cycle during deep events.
- 1U is tight. Confirm rack depth against the PSI5-1000RM1201UN's physical dimensions before ordering — especially in wall-mount enclosures or shallow 2-post open-frame racks where depth is constrained. The SNMP card occupies the rear communication slot, so verify no physical conflict with your cable management.
This unit is well-matched to a line-interactive UPS deployment in a security operations head-end or IDF closet: enough real-power headroom for a full NVR + switch load, SNMP management out of the box for remote monitoring, and pure sine wave output that won't destabilize modern active-PFC power supplies during a grid event.
