Is the internal mic supposed to completely shut off while headphones are connected? Brand new verizon s4, Is anyone able to make phone calls through an AUX cable while driving? I can hear the caller, but the phones mic seems to become completely inactivated if there is ANY cable plugged into the 3.5mm jack. I tested another brand new aux cable, and while plugged in I can't use google voice at all, it just detects nothing. Please let me know if this is as designed (can't imagine?) or if I have a defective brand new phone.. Thanks so much in advance. Verizon Galaxy S4 completely stock, most recent update.