APC Back-UPS 600 BK600 Uninterruptible Power Supply UPS 400W 120V 4-Outlet

APC Back-UPS 600 BK600 Uninterruptible Power Supply UPS 400W 120V 4-Outlet

The APC Back-UPS 600 (model BK600) is a desktop uninterruptible power supply rated at 600 VA / 400 watts. It provides battery backup and surge protection for desktop computers and peripherals, keeping connected equipment running through short power outages and protecting against surges and line noise. This unit was manufactured in the USA and includes a DB-9 serial interface for communication with a connected computer.

Specifications & What's Included

• Model: APC Back-UPS 600 (BK600)
• Capacity: 600 VA / 400 watts
• Input: 120V AC, 60Hz
• Input current: 360/450 5A; 520/600 7A (per rear label)
• Output: 120V AC, 60Hz
• Outlets: 4 x NEMA 5-15R (rear panel)
• Interface: DB-9 serial port (rear panel)
• Form factor: Desktop/tower
• Country of manufacture: USA
• Installed battery: CSB GP 6100 F2, 6V 10Ah (visible in photos — age and current capacity untested)
• No cables or manual included

Applications

The APC Back-UPS 600 was designed for home office and small business use, primarily to protect a desktop computer, monitor, and peripherals from power outages, surges, and voltage fluctuations. Introduced in the 1990s, this series was one of APC's most widely deployed consumer UPS lines and remains in use today as a cost-effective backup solution for legacy systems, network equipment, point-of-sale terminals, or any low-to-medium load requiring short-term power continuity. The DB-9 serial interface allows the UPS to communicate with a connected PC running APC's PowerChute software, enabling graceful shutdown during extended outages. Units like this are also commonly used as standby power for routers, modems, and small switches where keeping the network alive during a brief outage is the priority.