I’m trying to use Hologram SIM card on my project which uses an AiThinker A7 modem with a microsd card slot. I am located in Poland. Everything works as it should when I use SIM card from my local network. When I insert the Hologram card my modem does not seem to recognize it. AT+CCID returns error.
I use this socket for the SIM card. http://www.attend.com.tw/product_view.php?id=326.
Any idea on what is causing this behaviour? I am reading about USIM 1.8 vs SIM 3.3V sim cards. Does the Horizon supply the 1.8 or 3.3V version?