I know that the P605 will not work with LTE. However I can confirm that my straight talk Sim card works and I am getting HSPA+ (ATT Straight Talk Card) Here is my situation. I purchased a sim car from AT&T and activated it on the Gophone plan.. $35 per month for 500 minutes and unlimited text and data. For some reason no matter what APN I put in I don't get any data. I got data the first night I set it up and now I get no data. I have a International Version of the Galaxy S4 running with a GoPhone dumb phone $50 per month unlimited everything. (AT&T system does not recognize the IMEI so it reverts it to a dumb phone). Why isn't it working for my Galaxy Note 10.1 2014. I figure $35 bucks isn't a bad deal. Please assist or am I dead in the water.