Rear view
1 Headphone jack
2 Mic jack
3 Compact flash slot
4 PC card slot
5 PC Card eject button
6 Security keyhole
7 Power jack
8 Universal serial bus (USB) connector
9 External-monitor connector
1
Line-in jack
11 LAN connector
12 Modem connector
1
6
8
10
7
9
70
ThinkPad X21
5
4
3
2
11
12