4 PC card slot
5 PC Card eject button
6 IrDA port
7 Security keyhole
8 Power jack
9 External-monitor connector
10 Universal serial bus (USB) connector
11 Line-in jack
12 LAN connector
13 Modem connector
6
5
4
3
2
1
7
11
9
12
13
8
10
101
Chapter 3. ThinkPad X20, X21, X22, X23