I could connect (with an usb adapter) a Huawei usb dongle that I normally use with my laptop computer and contains a SIM card for mobile internet and phone functions like SMS and phonecalls, but it doesn't seem that android (4.4.4) with my Asus Nexus 7 WiFi edition recognizes the device.
I have an Asus TM AC-1900 WiFi router at home. We have a Nexus 4, Nexus 5, Nexus 7, iPhone 6 Plus and notebook computers. They are all able to connect to Wifi when I get home. However, the new AT&T Samsung Galaxy S6 will randomly fail to connect to WiFi when I get home. It does manage to automatically connect some of the time but most of the time I have to remember to connect it manually.