Radio Frequency Interference, Theory of Operation

1.2 Radio Frequency Interference

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules and the Class B limits for radio noise emissions from digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communi- cations. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications.

However, there is no guarantee that interference will not occur in a particular installation. If this equipment causes interference to radio or television reception, which can be determined by turn- ing the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

nreorient the receiving antenna

nincrease the separation between the equipment and the receiver

nconnect the equipment to an outlet on a circuit different from that to which the receiver is connected

nconsult the dealer or an experienced radio/TV technician for help.

Shielded communications interface cables must be used with this product.

War ning: Changes or modifications to this unit not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

1.3 Theory of Operation

This high-performance, line-interactive, uninterruptible power source (UPS) provides clean, reli- able, AC power to computer systems — protecting them from power blackouts, brownouts, swells, sags, surges, and interference.

Normally, the UPS operates “on-line,” supplying power from the utility input to the load (work- station, server, or other device). The converter circuitry is used to maintain an optimal float charge level on the battery.

When the utility fails, the disconnect switch opens and the converter supplies AC power to the load. The loads operate normally until shut down or until the battery is exhausted. The UPS auto- matically transfers the load back to utility power and recharges the batteries when the line voltage returns to normal.

The UPS also provides surge protection and EMI/RFI filtering, as well as SmartBoost™ and SmartTrim™ (automatic voltage regulation), which corrects high and low input voltage without drawing power from the battery.