Why can't I send or receive emails or text messages while I'm on a phone call? I could do this on an Android phone, but not on the iPhone.
Due to the technology that Verizon and Sprint use for their legacy voice networks (CDMA), and the fact iPhones only have 1 radio, only iPhone 6 and 6Plus with Advanced CallIng (VoLTE) active can do simultaneous voice and data.