Dell OptiPlex E1 Service Manual page 13

For desktop connectivity, the OptiPlex E1 system includes the following ports:
25-hole, bidirectional parallel port with EPP/ECP and demand-mode DMA
support
Two USB ports
Two 9-pin serial ports
Two PS/2 ports (mouse and keyboard)
One 15-hole video connector
One RJ45 Ethernet NIC connector
Three audio jacks (microphone, line-in, and line-out) (optional)
See Figure 1-3 for I/O port identifiers.
The OptiPlex E1 system is equipped with a switch-selectable (115/230-VAC)
power supply that can operate from standard AC power outlets in the U.S. and
all international countries.
The OptiPlex E1 system has a special power supply that provides trickle
("flea") power to support the Wakeup On LAN feature when computer power
is off.
Figure 1-2 shows the front-panel features for the low-profile chassis; Figure 1-3
shows internal features of the chassis.
power button power indicator
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hard-disk drive
access indicator
reset button
diskette drive
removable
media device
diskette-drive
access indicator
System Overview 1-5