Lenovo ThinkCentre A57e - Manual (Page 14)

Locating connectors on the rear of your computer
Figure 2 shows the location of connectors on the rear of your computer. Some
connectors on the rear of your computer are color-coded to help you determine
where to connect the cables on your computer.
1 Voltage-selection switch
(some models)
7 USB connectors (4)
2 Power cord connector 8 Ethernet connector
3 Standard mouse connector 9 Microphone connector
4 Standard keyboard connector 10 Audio line-out connector
5 Serial port 11 Audio line-in connector
6 VGA monitor connector 12 Adapter card slots (4)
Figure 2. Rear connector locations
6 Hardware Installation and Replacement Guide