The APC UPS Lineup: Back-UPS, Smart-UPS, SRT and Easy UPS Explained

APC, now operating as APC by Schneider Electric, sells more distinct UPS families than most people realize, and the names overlap in confusing ways. This page is an orientation map, not a recommendation: it tells you what each family is designed to do, so you can narrow the field before you open individual spec sheets. Specific capacities, runtimes, prices and warranty terms change between generations and regions, so treat anything here as a starting point and confirm on the current data sheet.

The lineup at a glance

If you only remember one thing: Back-UPS means consumer, Smart-UPS means business. That split affects far more than price. It changes the waveform, the software, the accessory slots, and how long the product line tends to be supported with replacement batteries and firmware.

Back-UPS: the consumer range

Back-UPS is what most people see on a store shelf. The smaller models are standby units: the outlets pass utility power through a surge filter, and when voltage drops out of range a relay switches the load to the inverter. Many mid-size Back-UPS models add automatic voltage regulation (AVR), which makes them line-interactive: they can boost or trim a sagging or high voltage without going to battery. See UPS types explained for how these topologies differ.

Two physical layouts are common: a floor "tower" with outlets on the front or top, and a power-strip style unit with outlets along one face. Both typically split outlets into two groups: battery backup plus surge, and surge only. The surge-only group gets no power during an outage. That is fine for a laser printer or desk lamp, but it is the single most common reason a buyer's modem goes dark when the power fails.

The output on battery for entry Back-UPS models is usually a stepped approximation of a sine wave. For routers, modems, LED lighting and most small power bricks this is a non-issue. It becomes an issue with larger PCs, as covered below.

Back-UPS Pro: line-interactive for demanding desktops

Back-UPS Pro sits between the consumer and business ranges. Expect line-interactive operation with AVR, a status LCD on many models, and more battery-backed outlets. Many recent Back-UPS Pro models are advertised with pure sine wave output, which is what a high-wattage gaming PC or workstation with an active PFC power supply wants. Not every Back-UPS Pro in every market is pure sine, and older generations often were not, so read the "waveform type" line for the specific model rather than assuming from the family name.

Back-UPS Pro is often the right tier for a home office, a single NAS, or a gaming PC. It usually lacks the network card slot and hot-swap battery design of Smart-UPS, which matters more in a rack than on a desk.

Smart-UPS: SMT, SMX and SMC

Smart-UPS is APC's long-running business line, and the line-interactive members are grouped into families identified by model prefixes. Broadly:

• SMT: the mainstream Smart-UPS tower and rack line. Sine wave output, LCD interface, and on many models a slot for a Network Management Card.
• SMX: rack/tower convertible models that commonly support external battery packs for extended runtime, with a network card slot on many models.
• SMC: a more streamlined, cost-focused Smart-UPS family. It keeps sine wave output but typically drops some expandability, such as network card slots or extended battery support, depending on the model.

Many current Smart-UPS models carry a C suffix, which on these units generally indicates SmartConnect support (see the software section). Regional variants also use suffix letters to indicate 230 V international versions. Our guide to reading UPS model numbers walks through how to decode these strings, but always verify against APC's own product page because conventions shift between generations.

Some Smart-UPS families have also been offered with lithium-ion batteries in certain models and regions. These trade higher upfront cost for longer expected battery life and lower weight. Availability varies, so check whether the variant you are looking at is sold in your market. See lithium UPS pros and cons.

Smart-UPS On-Line (SRT): double conversion

The SRT family is online double conversion: utility AC is rectified to DC and the inverter runs continuously, so there is no transfer when the utility fails. Output voltage and frequency are regulated regardless of input. This is the right tool when input power is genuinely poor, when a generator's frequency wanders, or when the load cannot tolerate any transfer.

The costs are real: online units run warmer, their fans run constantly, and they draw more standby power than a line-interactive unit unless an efficiency or "green" mode is enabled (which reintroduces a short transfer). Larger SRT models may require a hardwired input or a high-current plug such as NEMA L5-30 or L6-30 in North America; see UPS outlets and plugs and hardwired vs plug-in UPS. For the topology decision itself, read line-interactive vs online.

Easy UPS: the value range

Easy UPS is a value line whose model list and availability differ considerably between regions. Some markets get line-interactive tower and rack models, and some also get online double-conversion models under the Easy UPS name. Expect a narrower accessory and management ecosystem than Smart-UPS. If you are comparing an Easy UPS online unit against an SRT, line up the network management options, battery expansion, and local service availability, not just the price.

How to pick within the lineup

Software and management

APC's management stack has several layers, and the right one depends on how many machines you need to protect.

• PowerChute Personal Edition: for Back-UPS and Back-UPS Pro over USB on a single Windows PC. Handles shutdown, alerts and some settings like sensitivity.
• PowerChute Serial Shutdown (and older Business Edition on legacy systems): for Smart-UPS connected by USB or serial to a server.
• PowerChute Network Shutdown: an agent installed on each server or hypervisor host that listens to a Network Management Card and shuts down in a coordinated order.
• Network Management Card (NMC): an add-in card for supported Smart-UPS models that provides a web interface, SNMP, email alerts and event logs. See UPS network management cards and SNMP.
• SmartConnect: cloud monitoring on many current Smart-UPS models with the C suffix, reporting status and alerts to a Schneider Electric portal through a network port on the UPS. It is monitoring-focused and is not a substitute for a network card when you need coordinated shutdown.

APC USB units are also widely supported by third-party tools. Linux users often use apcupsd or Network UPS Tools (NUT), and NAS platforms such as Synology and TrueNAS recognize many APC models natively. For a side-by-side of vendor software, see PowerChute and PowerPanel.

Battery replacement notes

APC sells replacement batteries as RBC cartridges (Replacement Battery Cartridge), identified by an RBC part number. A cartridge may be a single battery with connectors already fitted, or several batteries pre-wired in series on a carrier. APC's site has a lookup tool that maps a UPS model to its cartridge, and the cartridge number is often printed in the manual or on a label inside the battery door.

• Many Smart-UPS models allow hot-swapping the battery without shutting down the load; many Back-UPS models require you to power down. Check the manual before you start.
• Aftermarket cartridges and bare batteries exist for most RBC numbers. Quality varies; see OEM vs aftermarket UPS batteries for what to check.
• After a replacement, run a self-test and, on Smart-UPS, a runtime calibration so the runtime estimate is accurate. See self-test and runtime calibration.

Things that trip APC buyers up

1. Simulated sine on a PFC power supply. A large PC with an active PFC supply may shut off or click when an entry Back-UPS switches to battery. Pure sine models avoid this. Background: pure vs simulated sine wave and active PFC power supplies.
2. Plugging critical gear into surge-only outlets. The labels are small. Check which side of the unit says "battery backup".
3. Buying by VA. Two units with the same VA figure can have very different watt ratings. Size by watts; see VA vs watts.
4. Importing the wrong voltage variant. APC sells 120 V and 230 V versions of many models, with different plugs, outlets and sometimes different model suffixes. A 230 V unit will not work properly on a North American 120 V outlet, and vice versa.
5. Assuming a network card fits. Not every Smart-UPS has a card slot, and the supported card generation depends on the model and firmware.
6. Expecting the SRT to be quiet. Online units run fans continuously. Placing one in a bedroom or quiet office surprises people.

Warranty terms, including any connected-equipment protection policy, differ by family and region. Read UPS warranties and equipment guarantees for what those policies usually cover and exclude. If you are cross-shopping, our APC vs CyberPower and Eaton vs APC comparisons put the families side by side.