how to enable to work both at same time LAN and internet network cards on ubintu 14.04 LTS

If the drivers are installed, they are enabled. Plug a cable into the router and your Ethernet port, and establish WiFi connection. Open terminal, execute "ifconfig" - you will see both eth0 and wlan0 interfaces having IP addresses.
 

ex_bubblehead

Glorious
Moderator

Normally ifplugd is active and will autoswitch between wireless and wired (disabling the other interface in the process). Priority is given to wired.
 

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