Dell E521 specifications Drives, Connectors, Controls and Lights

connector size	124 pins
connector data width (maximum)	32 bits
PCI Express
connector	one x1
connector size	36 pins
connector data width (maximum)	1 PCI Express lane
PCI Express
connector	one x16
connector size	164 pins
connector data width (maximum)	16 PCI Express lanes
Drives
Externally accessible:
Bays	one 3.5-inch drive bay (FlexBay)
	two 5.25-inch drive bays
Available devices	Serial ATA drives (4), floppy drive, USB memory
	devices, CD/DVD drive, and Media Card Reader
Internally accessible:	two bays for 1-inch high serial ATA hard drives
Connectors
External connectors:
Video	15-hole connector
Network adapter	RJ-45 connector
USB	two front-panel and four back-panel USB 2.0-
	compliant connectors
Audio	six connectors for 7.1 support
System board connectors:
Serial ATA	four 7-pin connectors
Internal USB device	one 10-pin connector (supports two USB ports)
Floppy drive	one 34-pin connector
Fan	one 5-pin connectors
PCI 2.3	two 124-pin connectors
PCI Express x1	one 36-pin connector
PCI Express x16	one 164-pin connector
Front panel	one 40-pin connector
Processor	one 940-pin connector
Memory	four 240-pin connectors
Power 12V	one 4-pin connector
Power	one 24-pin connector
Controls and Lights
Front of computer:
Power button	push button
Power light	green light — Blinking green in sleep state; solid
	green for power-on state.
	amber light — Blinking amber indicates a problem
	with the power supply inside the computer. If the
	system cannot boot and there is a solid amber light,
	this indicates a problem with the system board (see
	"Power Problems" in your Owner's Manual).
Diagnostic lights	four lights on the front panel (see Diagnostic Lights.)
Standby power light	AUX_PWR_LED on the system board
Hard-drive activity light	green light — When the computer is reading data
	from or writing data to the hard drive.
LAN indicator light	green light — Solid green indicates that a LAN (local
	area network) connection is established.
Rear of computer:
Link integrity light (on integrated network	green light — A good connection exists between a 10
adapter)	Mbps network and the computer.