Yeah, currently the router is working well. I note that the router manufacturer's page: http://www.tplink.com/en/article/?faqid=400, which has the troubleshooting guide on 3G issue.

I dowload the latest firmware as your recommendation, currently it is recognized by the router. However, after I choose my ISP, it won’t connect. I never got the IP Address, Subnet Mask and so on,...

Region : Belgium Model : TL-MR3220 Hardware Version : V1 Firmware Version : 3.12.21 Build 120523 Rel.37880n ISP : 3G mobile My router TL-MR3420 does not connect to my 3G modem. I did all the steps...