what is that connectivity mentioned earlier which these phones use?
The have upgraded to LTE Advanced, with support for over 20 LTE bands with better speed and VoLTE support  for Voice Calling & WiFi support for 802.11ac for high speeds
IPhone 6
The expanded LTE connectivity on the iPhone 6 and iPhone 6 Plus is improved to LTE Advanced, with support for over 20 LTE bands (seven more than the iPhone 5s), for up to 150 Mbit/s download speed, and VoLTE support. Wi-Fi performance has been improved with support for 802.11ac specifications, providing speeds up to 433.0581 Mbit/s—which is up to three times faster than 802.11n, along with Wi-Fi Calling support where available. 
what operating system does the iphone 6 have iOS 8 what type of battery does it use? The iPhone 6 features a 6.91 Wh (1810 mAh) battery which company released this phone? Apple Inc what type of phone is the one mentioned above? It is a Smartphone with larger display, faster processor, upgraded cameras and improved LTE & Wi-Fi connectivity which were one of the first brands in the above type of phone? The iPhone 2G was the first brand of Apple Phones, followed by 3G, 3Gs, 4 and 4s and so on
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IPhone 6 [SEP] Connectivity
The expanded LTE connectivity on the iPhone 6 and iPhone 6 Plus is improved to LTE Advanced, with support for over 20 LTE bands (seven more than the iPhone 5s), for up to 150 Mbit/s download speed, and VoLTE support. Wi-Fi performance has been improved with support for 802.11ac specifications, providing speeds up to 433.0581 Mbit/s—which is up to three times faster than 802.11n, along with Wi-Fi Calling support where available. The iPhone 6 and iPhone 6 Plus adds support for near-field communications (NFC). It is initially used exclusively for Apple Pay—a new mobile payments system which allows users to store their credit cards in Passbook for use with online payments and retail purchases over NFC.