Lenovo T420 - Manual (Page 78)

3
Note: Plug the yellow cable into the jack labeled MAIN, and the blue cable into the jack labeled AUX
on the card.
If the computer you are servicing is a wireless WAN-ready model and does not have a wireless WAN card,
route the antenna cables and secure them with a tape as shown in the following figure.
72 ThinkPad T420 and T420i Hardware Maintenance Manual