Lenovo ThinkCentre A57e - Manual (Page 15)

Connector Description
Standard mouse connector Used to attach a mouse, a trackball, or other pointing devices
that use a standard mouse connector.
Standard keyboard
connector
Used to attach a keyboard that uses a standard keyboard
connector.
Serial port Used to attach an external modem, a serial printer, or other
devices that use a 9-pin serial port.
USB connector 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 six USB
devices, you can purchase a USB hub, which you can use to
connect additional USB devices.
Ethernet connector 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.
Audio line-out connector Used to send audio signals from the computer to external
devices, such as powered stereo speakers (speakers with
built-in amplifiers), headphones, multimedia keyboards, or the
audio line-in connector on a stereo system or other external
recording devices.
Audio line-in connector Used to receive audio signals from an external audio device,
such as a stereo system. When you attach an external audio
device, a cable is connected between the audio line-out
connector of the device and the audio line-in connector of the
computer.
Chapter 2. Overview 7