Yes, need to configure at least one of the deco units into router mode first, then switch to AP mode.

You can find it from here http://www.tp-link.com/en/products/list-4691.html Some work with USB modem. \ Or modem router like archer VR900 http://www.tp-link.com.au/faq-1202.html

Which router did you bridge the tplink with? Did you follow any instruction to configure WDS? http://www.tp-link.com/en/faq-227.html There is compatibility issue between different routers, even...

Did you contact tplink support to fix the problem? I think there is a beta

Check whether your USB dongle is listed as compatible. http://www.tp-link.com/en/faq-270.html You can try this as well: http://www.tp-link.com/en/faq-269.html

Verify that the modem has correctly recognized your Mobile ISP . Otherwise, select the box of Set the Dial Number, [/FONT][FONT=AktivGrotesk-Bold]APN, Username and Password manually and enter the...