Lenovo ThinkCentre M55e - Manual (Page 10)

Locating the connectors on the rear of your computer
The following illustration shows the location of connectors on the rear of the
computer.
1 Standard mouse connector 9 PCI Express 1x adapter or PCI Express
x16 graphics adapter connector (some
models)
2 Parallel connector 10 Audio line out connector
3 Ethernet connector 11 Microphone connector
4 Audio line in connector 12 USB connectors (2)
5 Power cord connector 13 USB connectors (2)
6 Voltage-selection switch (some
models)
14 VGA monitor connector
7 PCI adapter connectors 15 Serial connector
8 PCI Express 1x adapter or PCI
Express x16 graphics adapter
connector (some models)
16 Standard keyboard connector
2 Hardware Replacement Guide