Lenovo 415711U - THINKSTATION S20 TWR W3520 2.8G User Manual page 19

8. Connect any additional devices that you have. Your computer might not have
all the connectors that are shown.
1 USB connector
2 Serial port
3 Ethernet connector
4 IEEE 1394 connector
(optional)
5 eSATA connector
1 3
9 4
1 3
9 4
Used to attach a device that requires a Universal Serial Bus
(USB) connector, such as a USB keyboard, a USB mouse, a USB
scanner, or a USB printer. If you have more than 10 USB devices,
you can purchase a USB hub, which you can use to connect
additional USB devices.
Used to attach an external modem, a serial printer, or other
devices that use a 9-pin serial port.
Used to attach an Ethernet cable for a local area network (LAN).
Note: To operate the computer within FCC Class B limits, use a
Category 5 Ethernet cable.
Used to send and receive IEEE 1394 signals between the
computer and other compliant devices, such as a video camera
or an external storage drive. This connector is sometimes called
Firewire.
Use this External Serial Advanced Technology Attachment
(eSATA) connector to attach an external hard disk drive.
Chapter 3. Setting up your computer
11